NSE4 · domain
Firewall Policies and NAT
Firewall Policies and NAT covers how FortiGate evaluates traffic: policy matching, NAT modes, VIPs, IP pools, and authentication. Questions use CLI scenarios, diagnose debug flow output, and policy configuration choices to test whether you can predict how traffic is permitted, translated, and logged.
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What to know about Firewall Policies and NAT
Be able to read a FortiGate policy and predict permit, deny, and NAT behavior, including VIP destination translation and SNAT pool selection. The most important thing is matching the correct source, destination, and service objects, then verifying with diagnose debug flow.
Order and matching of firewall policies, including implicit deny and policy lookup
Configuring SNAT with IP pools and central NAT versus policy NAT
VIP and virtual server configuration, including port forwarding and destination translation
FSSO and authentication conditions required for identity-based firewall policies
Why learners struggle
Why Firewall Policies and NAT questions are commonly missed
NAT questions are missed when learners confuse the four address types (inside local, inside global, outside local, outside global) or misapply the interface direction. A translation rule can look correct but still fail if the ACL, interface, or direction is wrong.
- ·Inside local vs inside global — inside local is the private source, inside global is the translated public address
- ·PAT overloads — many sources share one public IP using unique port numbers
- ·Interface direction — ip nat inside and ip nat outside must be on the correct interfaces
- ·Static NAT vs dynamic NAT vs PAT — each serves a different use case
- ·The NAT ACL identifies traffic to translate, not traffic to permit or deny
- ·A missing translation can look like a routing problem if the interfaces are misconfigured
Watch out for
Common Firewall Policies and NAT exam traps
- ▸Using the VIP external IP as destination in the policy instead of the VIP object, or confusing pre-translation and post-translation addresses in debug flow output
- ▸Forgetting that FSSO policies require the user to be authenticated and the FSSO collector agent or agentless polling to be reachable and working
- ▸Assuming NAT is applied automatically; SNAT requires an IP pool or outgoing interface address, and policy order determines whether NAT is applied
Question index
All Firewall Policies and NAT questions (193)
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A FortiGate has two firewall policies: Policy ID 1 (source: 10.0.1.0/24, destination: 203.0.113.0/24, action: allow, NAT: enabled) and Policy ID 2 (source: 10.0.1.0/24, destination: all, action: allow, NAT: enabled, IP pool: pool1). A user from 10.0.1.10 sends traffic to 203.0.113.5. Which policy will the traffic match and why?
Hard2An administrator configures a VIP for port forwarding: public IP 203.0.113.10 port 8080 to internal server 10.0.1.10 port 80. External users can connect to http://203.0.113.10:8080 but receive a timeout. The firewall policy allows traffic from any to the VIP on destination port 8080. The internal server is reachable from internal hosts. What is the most likely problem?
Hard3A FortiGate administrator needs to allow inbound SSH access from the internet to a single internal server at IP 10.0.1.10. The public IP on the WAN interface is 203.0.113.5. Which type of object should be configured to map the public IP and port to the internal server?
Easy4An administrator runs 'diagnose firewall iprope list 100000' and sees 'action=deny' entries for traffic that should be allowed. The policy list shows an allow policy with ID 1 for that traffic. What is the most likely cause of the deny?
Medium5An administrator needs to block access to specific websites based on their FQDN (e.g., *.example.com). The FortiGate should match the destination domain regardless of the IP address the domain resolves to. Which type of address object should the admin use in the firewall policy destination?
Easy6A FortiGate is configured with policy-based NAT and multiple IP pools. The administrator wants traffic from the 192.168.1.0/24 subnet to use IP pool 'POOL1' (203.0.113.1-203.0.113.10) and traffic from 192.168.2.0/24 to use IP pool 'POOL2' (203.0.113.11-203.0.113.20). Which THREE steps are necessary?
Hard7An organization has a FortiGate with two internet connections (WAN1 and WAN2). They want traffic to a specific web service (203.0.113.50 port 443) to always exit via WAN2. All other internet traffic should use WAN1. Which feature should be used to achieve this?
Hard8A FortiGate administrator wants to restrict access to a sensitive server (10.0.0.100) such that only users who authenticate via LDAP can access it. Which firewall policy configuration is required?
Easy9An admin notices that a firewall policy allowing inbound HTTPS to a server is not matching traffic. The policy has source set to 'all', destination to the server's IP, and service to HTTPS. The admin checks the policy list and sees that policy ID 1 matches the traffic. What is the MOST likely reason the intended policy (ID 10) is not matching?
Hard10An admin needs to allow outbound HTTP and HTTPS traffic from the internal network to the internet. Which two built-in service objects can be used in a single firewall policy to achieve this?
Easy11An administrator has configured a firewall policy that allows outbound traffic from a subnet to the internet, with NAT enabled. The external IP is 203.0.113.1. However, the administrator wants all traffic from a specific internal server (10.0.0.10) to appear with source IP 203.0.113.2. What should the administrator do?
Medium12A FortiGate administrator is configuring a Virtual IP (VIP) to allow external users to access an internal web server (192.168.1.10) using the public IP 203.0.113.10 on port 80. The admin creates a VIP with mapped IP 192.168.1.10 and port 80. A firewall policy is created from WAN to DMZ with destination set to the VIP. External users report that they can access the web server. What additional step is needed to allow the internal server to respond correctly?
Medium13An admin configures a VIP to map public IP 203.0.113.10 to internal server 10.0.1.100 on port 80. External users can reach the server via the public IP. However, internal users cannot access the server using the public IP. What is the MOST likely cause?
Medium14A FortiGate is configured with two policies: Policy A allows traffic from trust to untrust with schedule 'WorkHours' (Mon-Fri 9-17). Policy B allows traffic from trust to untrust with schedule 'Always'. A user sends traffic at 8:00 AM on Saturday. Which policy matches?
Hard15An admin configures a central SNAT rule to translate source IP 10.0.0.0/24 to IP pool 203.0.113.1-203.0.113.10 using overload (PAT). A policy-based NAT on a specific policy also translates the same source to the interface IP. Traffic from 10.0.0.0/24 to the internet shows source IP as the interface IP, not from the IP pool. What is the reason?
Hard16An admin runs 'diagnose sys session filter dport 443' and sees output showing sessions with 'proto=6' and 'expire=3599'. The admin notices that these sessions are not being cleaned up after the firewall policy that allowed them is deleted. What is the reason?
Medium17A company has a FortiGate with two ISPs: wan1 (primary) and wan2 (backup). They want all outbound traffic from internal users to use wan1, and if wan1 fails, traffic should automatically fail over to wan2. The administrator configures static routes: default route via wan1 gateway with distance 10 and default route via wan2 gateway with distance 20. They also configure an SD-WAN zone with both interfaces and set a strategy of 'Manual' with 'Best Quality' for wan1. After testing, failover does not occur when wan1 goes down. What is the most likely reason?
Easy18An admin needs to create a firewall policy that allows SMTP traffic (TCP/25) from the internal network (10.0.0.0/24) to a mail server in the DMZ (172.16.1.10). Additionally, the admin wants to ensure that the mail server can only be accessed by the internal network, not from the internet. Which THREE settings must be configured in the firewall policy? (Choose three.)
Medium19A FortiGate admin needs to allow inbound HTTPS traffic to a web server while also applying an application control profile to block certain web applications. The web server has a VIP configured. Which TWO components are necessary for this configuration?
Medium20What is the default action of the implicit deny policy at the end of the firewall policy list?
Easy21An admin runs the command 'diagnose firewall iprope list 100000' and sees the following output: id=2000000000 action=deny flag=0x0 src-interface=any dst-interface=any proto=0 src-addr=0.0.0.0-255.255.255.255 dst-addr=0.0.0.0-255.255.255.255 What does this entry represent?
Hard22An administrator configures a Central SNAT policy to translate traffic from the internal network (10.0.0.0/8) to the internet using the IP pool 'pool1'. The administrator also has a firewall policy that uses policy-based NAT with an IP pool 'pool2'. Both policies match the same traffic. Which NAT will be applied?
Hard23An administrator configures a Virtual IP (VIP) to map public IP 203.0.113.10 to internal server 10.0.1.10 on port 443. The firewall policy uses the VIP as the destination address. External users report they cannot connect. The administrator checks the policy and sees the destination interface is 'wan1' and source interface is 'wan1'. What is the most likely issue?
Hard24An administrator wants to allow access to an internal web server from the internet using a public IP address 203.0.113.10. The internal server has IP 10.0.0.5. Which FortiGate feature should be configured to translate the destination IP?
Easy25A FortiGate has a policy that allows traffic from 10.0.0.0/8 to any destination with NAT enabled using an IP pool 'Pool1' (203.0.113.10-203.0.113.20). The admin notices that internal servers using fixed ports (e.g., SIP) are failing. What is the likely cause?
Hard26A FortiGate administrator is troubleshooting why traffic from a specific host (10.0.1.100) to a web server (203.0.113.50) is being denied. The administrator has confirmed that a firewall policy exists that should allow the traffic. Which TWO diagnostic commands would help identify the issue?
Medium27A FortiGate has two firewall policies for HTTP traffic to the internet: Policy A (source: 10.0.1.0/24) and Policy B (source: 10.0.2.0/24). Both policies have the same destination and service. The admin wants to apply a traffic shaper to limit bandwidth for Policy B. Which TWO actions are correct? (Choose two.)
Medium28Which TWO statements about firewall policy order are true?
Easy29An administrator needs to block traffic from a specific geographic region (e.g., country) from reaching the corporate web server. Which type of address object should be used to define the source?
Medium30A FortiGate administrator wants to allow traffic from the internal network to a specific external server using its fully qualified domain name (FQDN) rather than an IP address, because the server's IP changes frequently. Which type of address object should the administrator create for the destination?
Easy31A FortiGate has a policy that enables NAT with an IP pool that uses overload (port address translation). The administrator notices that some applications are failing because they require a fixed source port range. What should the administrator do to resolve this?
Hard32An administrator needs to configure a firewall policy that allows internal users to access a specific web server on the internet using its domain name. The web server's IP address may change. Which type of address object should be used as the destination in the policy?
Medium33An administrator is configuring policy-based routing (PBR) on a FortiGate to route traffic from a specific subnet (172.16.1.0/24) through a different internet connection (wan2) instead of the default route via wan1. The administrator has created a PBR rule matching source 172.16.1.0/24 and set the gateway to the next-hop IP on wan2. The traffic is still using wan1. Which THREE of the following could be causing the issue? (Choose three.)
Medium34An admin is configuring a policy-based NAT rule (central NAT) to translate internal users' source IPs to the external IP of the FortiGate interface. However, users complain that some applications fail. The admin notices that the NAT rule is using 'dynamic IP pool' with overload. What is the MOST likely cause of the application failures?
Hard35An admin needs to configure NAT so that internal users (10.0.0.0/24) accessing the internet (any destination) are translated using an IP pool (203.0.113.10-203.0.113.20) with overload. The admin also needs to ensure that traffic from a specific server (10.0.0.100) always uses a fixed source port range (10000-20000) when translated. Which TWO configuration steps are required? (Choose two.)
Medium36An admin configures a firewall policy with a schedule object that restricts access to Monday to Friday from 9:00 to 17:00. A user attempts to connect on Saturday at 10:00. Which of the following best describes what happens?
Medium37A FortiGate administrator observes that traffic from a specific subnet is being denied even though there is an allow policy for that subnet. The administrator checks the policy list and sees an explicit deny policy above the allow policy. What should the administrator do to allow the traffic?
Medium38An admin needs to allow traffic from a specific IP to a web server on port 8080. The web server is behind a VIP that forwards port 80 to port 8080. When configuring the security policy, which destination should be used?
Medium39A FortiGate has multiple VDOMs. The administrator needs to allow traffic from VDOM A (port1) to VDOM B (port2). What type of firewall policy is required?
Medium40An admin configures an IP Pool with type 'Overload' for outbound traffic from the 192.168.1.0/24 subnet. The pool uses a single public IP 203.0.113.10. After a few hours, users are unable to access external websites. The admin checks the session table and sees many sessions with the same public IP and different source ports. What is the most likely issue?
Hard41An administrator configures a policy-based NAT rule to translate traffic from 10.0.0.0/8 to 203.0.113.1 using an IP Pool with overload. Later, they also enable Central SNAT for the same traffic. The traffic is not being NAT'd as expected. What is the MOST likely reason?
Hard42A FortiGate has two policies for traffic from port1 to port3: Policy 1 (destination 10.0.1.0/24, schedule always, action accept) and Policy 2 (destination 10.0.2.0/24, schedule 'Weekdays', action accept). A packet destined to 10.0.2.10 arrives on Wednesday at 2 PM. Which policy is applied?
Medium43An organization wants to authenticate VPN users using an LDAP server. They configure an LDAP server object and a user group. However, users are unable to authenticate. The administrator checks the logs and sees 'authentication failed' errors. What is the most common misconfiguration?
Hard44An administrator is creating firewall policies for a FortiGate that separates the internal network (10.0.1.0/24) from a DMZ (192.168.1.0/24). The goal is to allow HTTP traffic from the internal network to the DMZ web server (192.168.1.10) but deny all other traffic. What is the recommended security posture for the implicit deny policy?
Easy45An administrator configures a firewall policy allowing traffic from the internal network to the internet with NAT enabled. Users report that some outbound connections fail intermittently. The administrator runs 'diagnose sys session list' and sees many sessions in 'proto_state=01' with a short TTL. What is the most likely cause?
Medium46An administrator needs to ensure that a firewall policy applies only during business hours (Monday to Friday, 9:00 AM to 6:00 PM). What object should be configured and applied to the policy?
Medium47An administrator configures a Virtual IP (VIP) to map the public IP 203.0.113.10 port 8080 to the internal server 192.168.1.100 port 80. External users report they cannot connect. The firewall policy allows inbound traffic to the VIP. What is the MOST likely missing configuration?
Medium48A FortiGate administrator needs to block all traffic from a specific IP address (10.0.0.100) to the internet, but allow all other internal users. The administrator has created a firewall policy with source=10.0.0.100, destination=all, service=all, action=DENY, and placed it at the top of the policy list. Which TWO additional steps should the administrator take to ensure the block is effective? (Choose two.)
Easy49You run the following CLI command on a FortiGate: # diagnose debug flow filter saddr 192.168.1.10 # diagnose debug flow show function enable # diagnose debug enable You then initiate a ping from 192.168.1.10 to 8.8.8.8. The output shows 'no matching policy'. What does this indicate?
Medium50You execute 'get firewall policy 5' and see the following output: policyid=5 name="test" status=enable schedule="always" logtraffic=all What does 'logtraffic=all' mean?
Hard51Refer to the exhibit. An administrator configures the policies as shown. Traffic from 10.0.0.0/8 to the internet on HTTP is denied. What is the most likely reason?
Hard52An administrator is troubleshooting a FortiGate firewall policy that is supposed to allow HTTP traffic from the internal network to the internet. The policy is configured with source 'all', destination 'all', service 'HTTP', and action 'ACCEPT'. However, users report that HTTP traffic is being blocked. The administrator checks the policy list and sees that the policy is enabled. What is the most likely reason for the block?
Medium53A FortiGate administrator runs the following command and sees output: diagnose sys session filter dport 443 diagnose sys session list ... proto=6 proto_state=01 duration=3600 expire=3599 What does this output indicate about the session?
Medium54An administrator needs to block access to a specific website using FQDN address objects. Which TWO steps are necessary?
Medium55A FortiGate admin creates a new firewall policy with source address object 'Internal_Net' and destination 'All'. After saving, traffic from 'Internal_Net' is not matching the new policy but instead matches an older policy with a broader source. What is the MOST likely cause?
Medium56An admin wants to block all traffic from the internet to a specific internal server except for the IP address 203.0.113.50. Which firewall policy configuration achieves this using the principle of least privilege?
Easy57An administrator needs to allow VoIP traffic from a remote branch (192.168.2.0/24) to the main office (10.0.0.0/8) using UDP ports 5060 and 10000-20000. What is the most efficient way to define the service in the firewall policy?
Medium58A FortiGate administrator is configuring a firewall policy to allow inbound HTTPS traffic from the internet to an internal web server. The web server has a private IP address 10.0.0.10. The administrator wants to translate the destination IP to the internal server using a Virtual IP (VIP). Which TWO of the following must be configured for the VIP to work correctly? (Choose two.)
Medium59A junior admin is creating firewall policies and wants to ensure that all traffic not explicitly permitted is denied. Which FortiGate mechanism provides this behavior by default?
Easy60A FortiGate administrator configures a Central SNAT policy to translate internal IPs to a single public IP for internet access. However, traffic from a specific internal server (10.0.1.100) must use a different public IP. The administrator also creates a policy-based NAT rule in the firewall policy for that server. Which NAT method takes precedence?
Hard61An admin wants to block access to malicious websites using FortiGuard Web Filtering. Which policy configuration is necessary to apply the web filter profile to HTTP/HTTPS traffic?
Medium62An admin needs to create a firewall policy that matches traffic based on the destination being a specific geographic location (e.g., France). Which address object should be used?
Medium63A FortiGate administrator needs to create a firewall policy that allows traffic from the internal network to the DMZ. The internal network is 10.0.0.0/24 and the DMZ network is 172.16.0.0/24. Which source and destination address objects should be used in the policy?
Easy64A FortiGate administrator needs to configure source NAT for a group of internal servers (10.0.1.100-10.0.1.110) so that each server uses a unique public IP from the range 203.0.113.20-203.0.113.30. The requirement is that each internal IP maps to a fixed external IP (one-to-one mapping) and not port overload. Which TWO settings should be configured in the IP Pool? (Choose two.)
Medium65An organization has multiple remote sites connected via IPsec VPN. The administrator needs to ensure that traffic from the internal network (10.0.0.0/8) to the VPN destination (10.10.0.0/16) uses a specific interface (port2) instead of the default route. Which feature should be configured?
Medium66A FortiGate has two firewall policies: Policy 1 (ID 1) allows HTTP from any to 10.0.0.0/8, and Policy 2 (ID 2) denies all traffic from 192.168.1.0/24 to any. Traffic from 192.168.1.10 to 10.0.0.5 on port 80 is received. Which policy will match first?
Easy67A network administrator notices that traffic from the internal network (10.0.1.0/24) to the internet is not being matched by the intended firewall policy (ID 10). The policy uses source address 'internal_subnet' (10.0.1.0/24) and destination address 'all'. There is another policy (ID 5) with source 'all' and destination 'all' that also matches this traffic. What is the most likely reason policy 10 is not being matched?
Medium68A FortiGate admin has configured a firewall policy allowing traffic from the internal network (10.0.1.0/24) to the internet (any). Users report that they cannot access a specific website (203.0.113.5). The admin runs 'diagnose firewall fqdn list' and sees that the FQDN object used in a policy above the allow policy resolves to an IP that includes 203.0.113.5. What is the MOST likely cause?
Medium69Which address object type can be used to match traffic based on the source country?
Easy70An administrator is configuring traffic shaping on a firewall policy to limit bandwidth for YouTube. Which THREE components are required?
Hard71What is the purpose of a schedule object in a firewall policy?
Easy72An administrator needs to allow outbound DNS traffic (UDP port 53) from multiple internal subnets to the internet. Which object type should be used to group the subnets into a single source in the firewall policy?
Easy73You run the following command on a FortiGate: 'diagnose sys session filter dport 443' and see: proto=6 proto_state=01 duration=3600 expire=3599 What does this output indicate?
Hard74A FortiGate admin is troubleshooting an issue where internal users cannot access a specific external service over TCP/443. The admin confirms that the firewall policy allows HTTP/HTTPS. Which TWO CLI commands should the admin use to diagnose? (Choose two.)
Hard75An administrator needs to allow inbound SSH access from the internet to a specific internal server (10.0.1.10) on port 22. The WAN IP is 203.0.113.10. Which THREE configuration steps are required?
Medium76A FortiGate administrator wants to ensure that traffic from the internal network to the internet is translated to a single public IP address. Which NAT method should be used?
Easy77An administrator wants to limit the bandwidth for a specific application (e.g., YouTube) across all users. The administrator creates a traffic shaper and applies it to the firewall policy. What additional configuration is needed to identify YouTube traffic?
Medium78An admin configures a Central SNAT rule to translate internal 192.168.1.0/24 to 203.0.113.10 when accessing the internet. However, traffic from 192.168.1.100 to 8.8.8.8 shows source IP 192.168.1.100 in logs. What is the MOST likely cause?
Hard79A company has a web server in the DMZ that must be accessible from the internet on both HTTP and HTTPS. The admin configures a VIP to map the public IP to the server's private IP. However, external users can only reach HTTP. What is the MOST likely cause?
Medium80A network admin has configured a firewall policy allowing traffic from the 'internal' zone to the 'external' zone. The policy uses a service object 'HTTP' (TCP/80). Users report they can access HTTP websites but not HTTPS. The admin confirms no other policies block HTTPS. What is the most likely cause?
Medium81An admin wants to apply different QoS markings to traffic from two different departments. The admin creates two firewall policies: one for Sales (policy ID 1) and one for Engineering (policy ID 2). Both policies have traffic shaping enabled. However, traffic from both departments receives the same QoS marking. What is the MOST likely mistake?
Medium82A network admin configures a firewall policy allowing HTTP traffic from internal users to an external web server. The policy uses a service object 'HTTP' defined as TCP/80. However, users cannot reach the server. What is the MOST likely cause?
Medium83An administrator creates a firewall policy to allow outbound HTTP and HTTPS traffic from the internal network to the internet. The policy uses a dynamic IP pool for SNAT. Users report that some websites load slowly or fail to load intermittently. The administrator checks the firewall logs and sees 'session helper' warnings. What is the most likely cause?
Medium84Match each Fortinet product to its primary role.
Medium85Which address object type allows you to match traffic based on the domain name in the HTTPS SNI field?
Easy86What is the order of evaluation for firewall policies on a FortiGate?
Easy87A FortiGate policy allows traffic from the internal network to a DMZ server. The admin wants to limit access to only specific hours. Which object type should be used in the policy?
Easy88A company uses FSSO (Fortinet Single Sign-On) with a domain controller. Users authenticate to the domain, and the FortiGate retrieves the login events. The firewall policy uses the FSSO group. Some users report that after logging in, they cannot access resources that require authentication. The administrator checks the FSSO status and sees that the FortiGate is receiving login events. What is the most likely cause?
Medium89An administrator has configured a firewall policy with a destination NAT (DNAT) VIP to map public IP 203.0.113.5 to internal server 10.10.10.20 on port 443. The policy allows HTTPS traffic from the internet to the VIP. However, when testing from an internal client on the same subnet as the server, the connection to 203.0.113.5 fails. What is the most likely cause?
Hard90A FortiGate administrator is configuring a policy-based routing (PBR) rule to send all traffic from the 'Engineering' VLAN (10.1.0.0/16) to a dedicated internet link through gateway 203.0.113.1. The administrator also wants to apply a traffic shaper to limit bandwidth. Which THREE configuration tasks must be performed?
Hard91A FortiGate has multiple firewall policies. Policy ID 1 allows HTTP from LAN to WAN. Policy ID 2 allows all traffic from DMZ to WAN. A packet arrives from the DMZ interface destined to a web server on the internet using HTTPS. Which policy is matched?
Medium92An administrator notices that VoIP traffic (SIP) is not being inspected by the IPS profile applied to the firewall policy. The administrator suspects the traffic is being accelerated by NPU offloading. Which TWO actions can prevent NPU offloading for SIP traffic to ensure IPS inspection? (Choose two.)
Hard93An administrator needs to configure destination NAT for multiple internal servers using a single public IP address by differentiating based on destination port. The public IP 203.0.113.10 should map to: (A) 10.0.0.1:80 for HTTP, (B) 10.0.0.2:443 for HTTPS. Which TWO configuration steps are required? (Choose two.)
Hard94Which of the following is NOT a valid address object type in FortiGate?
Easy95An admin configures a firewall policy to allow SMTP traffic from a mail server to the internet with NAT enabled. External recipients report that the email source IP is the FortiGate's external interface IP. The admin wants the source to be a specific IP from a pool. What should the admin configure?
Medium96An admin wants to ensure that VoIP traffic (UDP ports 5060-5061) from the internal network to the internet is prioritized over other traffic when the WAN link is congested. Which feature should be configured on the firewall policy?
Medium97A FortiGate has a policy-based NAT rule that translates source IPs from subnet 192.168.1.0/24 to 203.0.113.10 when accessing the internet. The admin also enables Central SNAT with a rule that translates the same subnet to 203.0.113.20. If both are configured, which translation will be applied to traffic from 192.168.1.0/24 to the internet?
Hard98An admin configures a policy-based NAT rule (central SNAT) to translate source IPs from 10.0.0.0/24 to a dynamic IP pool of 203.0.113.1-203.0.113.10 with overload enabled. Users report that some connections are dropped. What is the MOST likely cause?
Hard99An administrator uses 'diagnose sys session list' and sees the following output for a session: 'proto=6 proto_state=01 duration=3600 expire=3599'. The session is for HTTPS traffic. What does 'proto_state=01' typically indicate in FortiGate?
Hard100A FortiGate administrator has configured a firewall policy with source NAT using an IP pool that contains two IP addresses: 203.0.113.10 and 203.0.113.11. The pool type is set to 'Overload'. The administrator notices that some outbound connections are failing, and when checking the session table, sees that many sessions are using the same source IP and port. What is the most likely cause of the connection failures?
Hard101A FortiGate administrator has enabled central NAT (policy-based NAT) in the VDOM. They need to translate all outbound traffic from the internal subnet 192.168.1.0/24 to the FortiGate's WAN interface IP when it leaves the network. Where must the NAT configuration be referenced in the firewall policy?
Medium102A network administrator has configured a firewall policy allowing traffic from the internal network (10.0.0.0/8) to the internet. Users report that some websites are not loading. The administrator runs 'diagnose firewall iprope list 100000' and sees the policy listed with a hit count of zero. What is the MOST likely cause?
Medium103An administrator is configuring a firewall policy to allow web traffic from the internal network to the internet. They want to apply security profiles and ensure that only HTTP and HTTPS are allowed. Which two actions are required in the firewall policy configuration? (Choose two.)
Medium104An admin wants to allow traffic only from specific countries to access a web server. Which type of address object should be used in the firewall policy?
Easy105An admin needs to translate the source IP of traffic from multiple internal hosts to a single public IP when accessing the internet, while keeping track of each session. Which NAT method should be used?
Easy106An administrator is troubleshooting why traffic from a specific subnet (192.168.10.0/24) to the internet is not being matched by the expected firewall policy. The policy list shows an allow policy for this traffic at ID 10, but there is a deny policy at ID 5 for any traffic from 192.168.0.0/16. Which TWO statements are correct?
Medium107A FortiGate administrator has configured a firewall policy allowing HTTP traffic from the internal network (10.0.1.0/24) to the DMZ server (192.168.1.10). The policy is placed after a deny-all policy that blocks traffic from internal to DMZ. Even though the allow policy is more specific, traffic is still being denied. What is the most likely cause?
Medium108An administrator is troubleshooting why traffic from a specific VLAN (192.168.10.0/24) to the internet is not being NATed correctly. The firewall policy allows the traffic with NAT enabled and uses an IP Pool (overload) for the source translation. The IP Pool is configured with the address 203.0.113.10. However, the traffic still shows the original source IP. Which THREE of the following could cause this issue? (Choose three.)
Hard109Which statement about the implicit deny policy on a FortiGate is true?
Easy110An admin is configuring a policy-based NAT (central SNAT) to translate internal users to a pool of public IPs using overload. The admin wants to ensure that specific applications using non-standard ports are not affected by NAT. Which THREE steps should the admin consider?
Hard111A network admin runs 'diag sys session filter proto 6' and 'diag sys session list' and sees many sessions with state 'SYN_SENT' to a public web server. The firewall policy allows TCP/443. What is the MOST likely cause?
Medium112A company has two internet connections (WAN1 and WAN2). The administrator wants to route HTTP traffic from the internal network through WAN1, and all other traffic through WAN2. Which TWO configurations are needed?
Medium113Which of the following is a characteristic of policy-based NAT on a FortiGate?
Easy114An administrator is configuring a firewall policy on a FortiGate to allow internal users to access a web server on the internet. The administrator wants to log all traffic that matches this policy. Which logging option should be enabled on the policy to log traffic at the session start and end?
Easy115Which statement best describes the 'implicit deny' policy on a FortiGate?
Easy116A network admin has configured a firewall policy allowing HTTPS traffic from the internal network to a DMZ web server. Users report that the web pages load slowly. The admin checks the policy and notices traffic shaping is not applied. What is the BEST action to ensure fair bandwidth distribution for HTTPS traffic?
Medium117A FortiGate administrator configures a firewall policy to allow HTTP traffic from internal users to the internet. The policy uses source address 'internal_subnet', destination address 'all', and service 'HTTP'. After applying the policy, users report they cannot access websites. What is the most likely cause?
Easy118A FortiGate administrator needs to allow SMTP traffic (TCP port 25) from the internal network (10.0.0.0/8) to a mail server in the DMZ (172.16.0.10). The administrator wants to apply an antivirus profile and log all sessions. Which THREE configuration steps are required?
Medium119An administrator needs to apply traffic shaping to limit bandwidth for video streaming traffic on a firewall policy. Which configuration step is required?
Medium120An administrator wants to restrict access to a web server from only specific countries. The FortiGate is located at the network edge. Which address object type should be used in the source field of the firewall policy?
Easy121A FortiGate administrator is implementing a policy to allow outbound traffic from the internal network to the internet. The requirements are: (1) all traffic from internal users must be source NATed to the external interface IP, (2) traffic from a specific server must use a different public IP, (3) HTTP traffic must be shaped to 10 Mbps. Which THREE configuration elements should the administrator create? (Choose three.)
Medium122A FortiGate administrator wants to ensure that traffic from the 192.168.1.0/24 network to the internet is translated to a single public IP address using overload (PAT). Which NAT configuration should be used?
Medium123Given the exhibit, a user in the internal network tries to SSH to a public server (203.0.113.10). What will happen and why?
Medium124A FortiGate administrator wants to ensure that traffic from the internal network to an external FTP server uses a specific source IP address (203.0.113.10). The internal network uses RFC 1918 addresses. Which NAT configuration should be used?
Medium125An administrator creates a firewall policy with a traffic shaper to limit bandwidth for guest wireless users. After applying the policy, users can still consume high bandwidth. The administrator confirms the policy is matching. What is the MOST likely reason the traffic shaper is not effective?
Medium126An organization needs to restrict internet access for employees to business hours only (Monday to Friday, 8:00 to 18:00). Which object should the admin use in the firewall policy?
Medium127A FortiGate admin is creating a firewall policy to allow outbound HTTP and HTTPS traffic from the internal network. The admin wants to ensure that traffic is inspected by security profiles (antivirus, web filter). Which THREE of the following must be configured on the firewall policy to achieve this?
Easy128A FortiGate admin configures an IP pool with type 'Fixed Port Range' to translate source IPs from 192.168.1.0/24 to 203.0.113.0/28 using port range 10000-20000. After applying the IP pool to a policy, some users cannot establish connections while others work. What is the MOST likely cause?
Hard129Which of the following describes the implicit deny action in FortiGate firewall policies?
Easy130A FortiGate admin is troubleshooting an issue where traffic from VLAN 10 to the internet is not being NATed even though a policy-based NAT rule is configured. The admin verifies that the firewall policy uses the correct IP Pool. Which THREE steps should the admin take to diagnose the problem? (Choose three.)
Hard131A FortiGate administrator wants to create a firewall policy that matches traffic based on the destination domain name (e.g., *.example.com). Which type of address object should be used?
Easy132An administrator needs to configure a firewall policy to allow outbound traffic from the internal network to the internet. The internal network uses private IP addresses, and the FortiGate's WAN interface has a public IP. Which NAT configuration is appropriate to ensure return traffic is routed correctly?
Medium133An admin wants to block all traffic from a specific geographic region. Which address object type should be used in the firewall policy source?
Medium134A FortiGate with multiple VDOMs has a policy that allows traffic from VDOM A to VDOM B. The admin notices that traffic from VDOM A to a specific server in VDOM B is being dropped. The session log shows 'deny by forward policy check'. What is the MOST likely cause?
Hard135A company has a web server in the DMZ that needs to be accessible from the internet on port 443 (HTTPS). The administrator configures a Virtual IP (VIP) mapping the public IP 203.0.113.10 to the private IP 10.0.1.10 port 443. Which firewall policy is required to allow inbound traffic?
Medium136A FortiGate administrator needs to create a firewall policy that allows traffic from the internal network (10.0.0.0/8) to a public web server (203.0.113.10) on port 443. The policy must also perform source NAT using the FortiGate's external IP (198.51.100.1). Which NAT configuration should be applied?
Medium137Which of the following best describes the policy lookup order on a FortiGate firewall?
Easy138A FortiGate admin runs 'diagnose sys session filter src 10.0.0.10' and gets no output. What does this indicate?
Medium139A FortiGate has a central SNAT policy that translates internal users to a single IP pool address. The admin wants specific traffic (e.g., from a particular subnet) to use a different IP pool. What is the correct approach?
Hard140A company has a FortiGate with multiple VDOMs. An admin creates a firewall policy in the root VDOM to allow traffic from a subnet to the internet. The traffic is not matching the policy. What is the most likely cause?
Medium141Which of the following statements about firewall policy ordering in FortiGate is correct?
Easy142An admin needs to configure a FortiGate to allow multiple internal servers to be accessible from the internet using the same public IP but different ports. For example, internal server A (192.168.1.10:80) should be reachable via 203.0.113.10:8080, and internal server B (192.168.1.20:443) via 203.0.113.10:8443. Which TWO configuration steps are required?
Hard143A FortiGate admin wants to ensure that traffic destined to a specific web server is inspected by an IPS profile. Which configuration is necessary?
Easy144During a security audit, the administrator runs the command 'diagnose firewall policy list' and sees the following output: policy id=1: allow from port1 to port2, src=10.0.0.0/8, dst=any, action=accept policy id=2: deny from port1 to port2, src=10.0.0.0/8, dst=172.16.0.0/12, action=deny policy id=3: allow from port1 to port2, src=any, dst=any, action=accept A host with IP 10.0.1.5 sends traffic to 172.16.0.1. Which policy will match?
Hard145An admin creates a firewall policy allowing HTTP traffic from internal users to the internet. Users complain that they cannot access HTTPS websites. The admin checks and sees that the policy only has HTTP service. What is the BEST course of action to allow HTTPS while maintaining security?
Medium146An administrator wants to configure traffic shaping to limit bandwidth for YouTube video streaming. Which THREE objects or settings must be configured on the FortiGate to apply traffic shaping?
Medium147A FortiGate is configured with multiple policies. The first policy allows traffic from 10.0.0.0/8 to any destination. The second policy denies traffic from 10.0.1.0/24 to any destination. What happens when a packet from 10.0.1.5 to 8.8.8.8 arrives?
Hard148A FortiGate has multiple WAN interfaces (port1, port2) connected to different ISPs. The administrator wants traffic from the internal network to use port1 for general internet access but use port2 for traffic to a specific cloud service (203.0.113.0/24). Which feature should be used to achieve this?
Medium149A FortiGate admin needs to block all traffic from the 'Guest' VLAN (192.168.100.0/24) to the internal network (10.0.0.0/8) except for DNS traffic (UDP 53) to the internal DNS server at 10.0.0.10. Which TWO firewall policy configuration elements are required to achieve this? (Choose two.)
Medium150A network admin needs to configure a FortiGate to allow remote VPN users (IPsec VPN) to access a web server in the DMZ. The VPN users are assigned IPs from 10.10.10.0/24. The web server is at 192.168.2.10:80. Which TWO objects must be created to define the traffic for the firewall policy? (Choose two.)
Medium151Drag and drop the steps to create a firewall policy allowing HTTP traffic from internal to DMZ into the correct order.
Medium152Which statement best describes the implicit deny policy at the end of a FortiGate policy list?
Easy153A FortiGate administrator needs to ensure that all internal users (10.0.0.0/8) accessing the internet use a single public IP address 203.0.113.10 for source NAT. Which NAT configuration should be used?
Easy154A FortiGate administrator needs to allow all internal users (10.0.0.0/8) to access a web server in the DMZ (192.168.1.100) using HTTPS. The administrator wants to apply a web filter profile to block malicious URLs while allowing legitimate traffic. Which of the following is the correct policy configuration?
Easy155A FortiGate with multiple WAN interfaces uses policy-based routing (PBR) to route traffic from a specific subnet out of a particular interface. The admin also has a firewall policy allowing that subnet to the internet. However, the traffic is not being routed as expected. What could be the issue?
Hard156A FortiGate admin configures a firewall policy to allow outbound HTTP traffic and applies a web filter profile. The admin notices that some users can access a known malicious URL while others are blocked. All users are in the same source subnet (10.0.1.0/24). What is the MOST likely cause of this inconsistent behavior?
Hard157An administrator configures a firewall policy with source address 'internal_net' (10.0.0.0/16) and destination address 'server_farm' (10.10.10.0/24). The action is set to ACCEPT with NAT enabled. However, traffic from 10.0.1.100 to 10.10.10.50 is being denied. What is the most likely cause?
Medium158Which of the following statements about FortiGate policy lookup order is correct?
Easy159A FortiGate administrator needs to ensure that traffic from the LAN (192.168.1.0/24) to the DMZ (10.0.0.0/24) uses a specific outbound interface (port3) instead of the default route. Which feature should be configured to achieve this?
Medium160A network admin needs to log all traffic from the sales VLAN to the internet. The firewall policy is configured with logging enabled. However, the admin notices that only session start logs are generated, not detailed traffic logs. What setting must be enabled to capture per-packet or per-session details?
Medium161A FortiGate admin wants to create a firewall policy that allows traffic from the internal network to the internet. The source is a subnet 192.168.1.0/24, and the destination is 'all'. The admin wants to apply NAT to hide internal IPs. Which NAT configuration is BEST suited for this scenario?
Medium162Which of the following best describes a Virtual IP (VIP) in FortiGate?
Easy163An administrator needs to configure a firewall policy to allow outbound traffic from the internal network to the internet. The internal network uses private IP addresses, and the administrator wants to hide these addresses from the internet. Which NAT configuration should be applied to the policy?
Easy164Which TWO statements about firewall policy authentication are correct?
Medium165Which statement about the implicit deny policy at the bottom of the firewall policy list is true?
Easy166An administrator configures a firewall policy with a schedule object that is set to 'Available: Mon-Fri 09:00-17:00'. At 10:00 AM on Saturday, users report they cannot access the resource. The administrator checks the policy list and sees the policy is enabled. What is the MOST likely reason?
Hard167An administrator needs to translate a single internal server (192.168.1.10:8080) to a public IP (203.0.113.10:80) so that external users can access it via HTTP. Which type of VIP should be configured?
Medium168A network administrator needs to allow only HTTPS traffic from the internal network (10.0.0.0/8) to the public DNS server (8.8.8.8). Which firewall policy configuration BEST enforces this restriction?
Easy169A FortiGate has policy-based NAT enabled. The admin wants to translate the source IP of internal users to the interface IP for internet traffic. The firewall policy has NAT enabled. However, traffic from the internal network to the internet shows the original source IP instead of the interface IP. What is the MOST likely reason?
Hard170An administrator needs to block all traffic from a specific geographic region. Which object type should be used as the source in the firewall policy?
Easy171An administrator configures a firewall policy with a schedule that allows traffic only during business hours (Monday to Friday, 09:00-18:00). At 17:55 on a Friday, a user establishes an SSH session that is still active at 18:05. What happens to the session when the schedule ends?
Medium172An administrator needs to configure outbound NAT for 200 internal users using a single public IP (203.0.113.1). The public IP provides 2000 ports. Some applications require a deterministic source port range for logging. Which TWO NAT settings should be used?
Hard173A FortiGate administrator is troubleshooting a connectivity issue where internal clients cannot reach a public web server. The administrator has confirmed that routing is correct and there are no security profiles blocking traffic. Which TWO debugging steps should the administrator take? (Choose two.)
Medium174An administrator wants to create a firewall policy that blocks all traffic from a specific IP address (10.0.0.99) to the internet, but allows all other traffic. Which policy configuration is correct?
Easy175Which firewall policy matching parameter is evaluated FIRST when a packet arrives at a FortiGate interface?
Easy176An administrator needs to allow internal users to access a public web server using the server's private IP address, while external users access it via a public IP. Which TWO components are required?
Medium177An organization requires that outbound HTTP and HTTPS traffic from the internal network be translated to a single public IP address (203.0.113.1) using overload NAT (PAT). Which TWO configurations are necessary?
Hard178An admin needs to allow inbound SMTP traffic from the internet to a mail server in the DMZ. The public IP is 203.0.113.10, and the mail server's private IP is 10.0.0.5. Which VIP configuration is correct?
Medium179An administrator configures Central SNAT with a dynamic IP pool for internet-bound traffic. Some users report that certain applications fail when they should be translated to a specific public IP. The administrator checks the policy-based NAT rules and finds none. What is the most likely reason for the failure?
Hard180An organization wants to implement least privilege for firewall policies. Which THREE best practices should be followed? (Choose three.)
Medium181What is the purpose of the 'implicit deny' policy on a FortiGate?
Easy182A network administrator creates a firewall policy allowing HTTP traffic from the internal network to a web server in the DMZ. Users report that they cannot access the web server. The administrator runs 'diagnose firewall iprope list' and sees the policy is present. What is the MOST likely cause of the issue?
Medium183An admin wants to block traffic from a specific geographic region (e.g., North Korea) from reaching the FortiGate's external interface. Which address object type should be used in the firewall policy?
Medium184An administrator wants to log all traffic that is denied by the implicit deny rule. How can this be achieved?
Medium185A FortiGate administrator configures a policy-based NAT using an IP pool with type 'Fixed Port Range' for internal users accessing a specific external server. Users report that after some time, they cannot establish new connections to the server. 'diagnose ip pool list' shows many entries with 'used_port=65535'. What is the MOST likely cause?
Hard186A FortiGate administrator needs to block all traffic from a specific geographic region (country) from accessing the internal network. Which type of address object should be used in the firewall policy?
Easy187When creating a firewall policy, an admin wants to ensure that traffic from a specific user group is allowed only during business hours (Monday to Friday, 09:00-18:00). Which object type must be configured and applied to the policy?
Medium188An administrator is configuring a VIP to map a public IP to an internal server. The server hosts both HTTP and HTTPS services. The admin creates a VIP with port forwarding for port 80 to internal port 80, and another VIP for port 443 to internal port 443. Both VIPs use the same public IP. Users can access HTTP but not HTTPS. What is the most likely issue?
Hard189Which THREE conditions must be met for a firewall policy with FSSO authentication to work correctly?
Hard190A FortiGate administrator needs to allow SMTP traffic from the internal network to an external mail server. The internal network uses source NAT to the external interface IP. Which firewall policy configuration is correct?
Easy191An admin configures a VIP to map a public IP to an internal server. The firewall policy uses the VIP as the destination. External users can access the server, but the server's logs show the source IP as the FortiGate's internal interface IP instead of the original client IP. Why is this happening?
Hard192What is the purpose of policy-based routing (PBR) in FortiGate?
Easy193A company uses FortiGate with firewall policies to control access between internal VLANs. Users in VLAN 10 report they can access internet but cannot reach a server in VLAN 20 on port 443. The server is reachable from other VLANs. The administrator checks the firewall policy configuration: there is a policy from VLAN10 to VLAN20 allowing HTTPS, with NAT disabled and logging enabled. The policy has a schedule set to 'Always'. The administrator also checks that there are no overlapping policies. What is the most likely cause?
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Frequently asked questions
- What does the Firewall Policies and NAT domain cover on the NSE4 exam?
- Be able to read a FortiGate policy and predict permit, deny, and NAT behavior, including VIP destination translation and SNAT pool selection. The most important thing is matching the correct source, destination, and service objects, then verifying with diagnose debug flow.
- How many questions are in this domain?
- This page lists all 193 Firewall Policies and NAT questions in the NSE4 question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
- What is the best way to practise this domain?
- Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
- Can I practise only Firewall Policies and NAT questions?
- Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.