NAT and DHCP

A network engineer is configuring a Cisco router to provide internet access to a small office using a single public IP address assigned by the ISP. The engineer wants to allow internal hosts to initiate connections to the internet, but also needs to make a web server on the internal network reachable from the internet. The engineer configures a standard access list for NAT and an ip nat inside source list command. However, external users cannot reach the internal web server. What is the most likely cause?

Question 3mediummultiple choice

A network engineer is troubleshooting a DHCP issue on a Cisco router configured as a DHCP server for a VLAN. Clients in the VLAN are able to obtain IP addresses from the DHCP server, but they are not receiving the correct DNS server address. The engineer checks the DHCP pool configuration and sees the dns-server command is configured with the correct IP address. What is the most likely cause of the problem?

Question 4hardmultiple choice

A network engineer is configuring NAT overload (PAT) on a Cisco router to allow multiple internal hosts to share a single public IP address. The engineer uses the command ip nat inside source list 1 interface GigabitEthernet0/0 overload. After testing, internal hosts can access the internet, but some applications fail intermittently. The engineer suspects a NAT issue. What is the most likely cause?

Question 5mediummultiple choice

A network engineer is configuring a Cisco router as a DHCP relay agent to forward DHCP requests from a client VLAN to a centralized DHCP server located in a different subnet. The engineer configures the ip helper-address command on the VLAN interface. However, clients in the VLAN are not receiving IP addresses. The DHCP server is reachable from the router. What is the most likely cause?

Question 6hardmultiple choice

A network engineer is troubleshooting a NAT issue where an internal host cannot establish an SSH session to a remote server on the internet. The engineer checks the NAT translations on the border router and sees that the translation for the host's source IP is present. However, the SSH session times out. The engineer also notices that the remote server's IP is not in the NAT translation table. What is the most likely cause?

Question 7easymultiple choice

A network engineer is configuring a Cisco router to act as a DHCP server for a branch office. The engineer creates a DHCP pool for the 192.168.1.0/24 subnet and configures the default-router, dns-server, and domain-name options. However, clients are able to obtain IP addresses but cannot ping the default gateway. The engineer verifies that the router's interface IP is 192.168.1.1. What is the most likely cause?

Question 8easymultiple choice

A network engineer is configuring NAT on a Cisco router to allow internal hosts to access the internet. The engineer uses the command ip nat inside source list 100 interface GigabitEthernet0/0 overload, where access list 100 permits only the 10.0.0.0/8 network. After testing, hosts in the 10.0.0.0/8 network can access the internet, but hosts in the 172.16.0.0/16 network cannot. The engineer verifies that the 172.16.0.0/16 hosts have connectivity to the router. What is the most likely cause?

Question 9mediummultiple choice

A network engineer is troubleshooting a DHCP issue where a client is not receiving an IP address from a Cisco router configured as a DHCP server. The engineer checks the DHCP pool configuration and sees that the network command is configured with the correct subnet. The engineer also verifies that the ip dhcp excluded-address command is not blocking any addresses. However, the client's DHCP discover message is not reaching the router. What is the most likely cause?

Question 10hardmultiple choice

A network engineer is configuring NAT on a Cisco router to allow internal hosts to access the internet. The engineer uses the command ip nat inside source static tcp 192.168.1.10 80 203.0.113.1 80. After testing, external users can access the internal web server using the public IP. However, internal hosts cannot access the web server using the public IP. What is the most likely cause?

Question 11mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip nat translations

Pro Inside global Inside local Outside local Outside global --- 192.0.2.10 10.0.0.10 --- --- --- 192.0.2.11 10.0.0.11 --- ---

Based on this output, what can be concluded?

Question 12mediummultiple choice

A network engineer runs the following command on Router R2:

R2# debug ip dhcp server events
*Mar  1 00:05:23.123: DHCPD: DHCPDISCOVER received from client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30 on interface GigabitEthernet0/1
*Mar  1 00:05:23.124: DHCPD: Sending DHCPOFFER to client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30 (10.0.0.2)
*Mar  1 00:05:23.125: DHCPD: DHCPREQUEST received from client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30
*Mar  1 00:05:23.126: DHCPD: Sending DHCPACK to client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30 (10.0.0.2)

Based on this debug output, what can be concluded?

Question 13hardmultiple choice

A network engineer runs the following command on Router R3:

R3# show ip nat statistics

Total active translations: 5 (0 static, 5 dynamic; 5 extended) Outside interfaces: GigabitEthernet0/0 Inside interfaces: GigabitEthernet0/1 Hits: 1234 Misses: 5 CEF Translated packets: 1200, CEF Punted packets: 34 Expired translations: 10 Dynamic mappings: -- Inside Source

[Id] ip nat pool POOL1 203.0.113.1 203.0.113.10 netmask 255.255.255.240

refcount 5

Based on this output, what can be concluded?

Question 14mediummultiple choice

A network engineer runs the following command on Router R4:

R4# show ip dhcp binding

Bindings from all pools not associated with VRF:

IP address       Client-ID/              Lease expiration        Type

Hardware address/ User name

10.0.0.10        0063.6973.636f.2d30.    Mar 01 2025 12:00 PM   Automatic
                 3030.302e.3030.3030.
                 2e30.3030.312d.4574.

10.0.0.11        0063.6973.636f.2d30.    Mar 01 2025 12:05 PM   Automatic
                 3030.302e.3030.3030.
                 2e30.3030.312d.4574.

Based on this output, what can be concluded?

Question 15hardmultiple choice

A network engineer runs the following command on Router R5:

R5# show ip nat translations

Pro Inside global Inside local Outside local Outside global udp 192.0.2.20:1234 10.0.0.20:1234 203.0.113.1:53 203.0.113.1:53 tcp 192.0.2.20:5678 10.0.0.20:5678 198.51.100.1:80 198.51.100.1:80

Based on this output, what can be concluded?

Question 16mediummultiple choice

A network engineer runs the following command on Router R6:

R6# show ip dhcp conflict
IP address       Detection method     Detection time         VRF
10.0.0.10        Ping                 Mar 01 2025 10:00 AM   default
10.0.0.15        Gratuitous ARP       Mar 01 2025 10:05 AM   default

Based on this output, what can be concluded?

Question 17mediummultiple choice

A network engineer runs the following command on Router R7:

R7# show ip nat translations verbose

Pro Inside global Inside local Outside local Outside global --- 192.0.2.10 10.0.0.10 --- --- create: 03/01/2025 09:00:00, use: 03/01/2025 09:05:00 timeout: never, flags: static --- 192.0.2.11 10.0.0.11 --- --- create: 03/01/2025 09:00:00, use: 03/01/2025 09:06:00 timeout: never, flags: static

Based on this output, what can be concluded?

Question 18hardmultiple choice

A network engineer runs the following command on Router R8:

R8# show ip dhcp server statistics

Memory usage: 12345 Address pools: 2 Database agents: 0 Automatic bindings: 10 Manual bindings: 2 Expired bindings: 1 Malformed messages: 0

Message Received

BOOTREQUEST    0

DHCPDISCOVER 100 DHCPREQUEST 95 DHCPDECLINE 1 DHCPRELEASE 2 DHCPINFORM 0

Based on this output, what can be concluded?

Question 19hardmultiple choice

A network engineer runs the following command on Router R9:

R9# show ip nat translations

Pro Inside global Inside local Outside local Outside global udp 192.0.2.20:1234 10.0.0.20:1234 203.0.113.1:53 203.0.113.1:53 tcp 192.0.2.20:5678 10.0.0.20:5678 198.51.100.1:80 198.51.100.1:80 --- 192.0.2.21 10.0.0.21 --- ---

Based on this output, what can be concluded?

Question 20mediummultiple choice

Consider the following configuration snippet: ```

interface GigabitEthernet0/1
 ip address 192.168.1.1 255.255.255.0
 ip nat inside

interface GigabitEthernet0/2
 ip address 203.0.113.1 255.255.255.0
 ip nat outside

ip nat inside source list 1 interface GigabitEthernet0/2 overload
access-list 1 permit 192.168.1.0 0.0.0.255

``` What is the effect of this configuration?

Question 21mediummultiple choice

Examine this DHCP configuration: ```

ip dhcp pool POOL1
 network 10.10.10.0 255.255.255.0

default-router 10.10.10.1 dns-server 8.8.8.8 lease 0 12 !

ip dhcp excluded-address 10.10.10.1 10.10.10.10

``` Which statement is true?

Question 22mediummultiple choice

Given this NAT configuration: ```

interface GigabitEthernet0/0
 ip address 10.0.0.1 255.255.255.0
 ip nat inside

interface GigabitEthernet0/1
 ip address 198.51.100.1 255.255.255.0
 ip nat outside

ip nat inside source static 10.0.0.5 198.51.100.5

``` What is the purpose of this configuration?

Question 23mediummultiple choice

Review the following DHCP relay configuration: ```

interface Vlan10
 ip address 192.168.10.1 255.255.255.0
 ip helper-address 172.16.1.100

``` What is the effect of the 'ip helper-address' command?

Question 24mediummultiple choice

Analyze this NAT configuration: ```

ip nat pool GLOBAL 203.0.113.10 203.0.113.20 netmask 255.255.255.0
ip nat inside source list 1 pool GLOBAL overload
access-list 1 permit 192.168.1.0 0.0.0.255

``` Which statement is correct?

Question 25mediummultiple choice

Examine this DHCP configuration: ```

service dhcp
ip dhcp pool POOL2
 network 10.20.20.0 255.255.255.0

default-router 10.20.20.1 lease infinite ``` What is the effect of the 'lease infinite' command?

Question 26easymultiple choice

What is the default lease time for a DHCP pool in Cisco IOS?

Question 27easymultiple choice

Which type of NAT translates multiple inside addresses to a single outside address using different port numbers?

Question 28mediummultiple choice

What is the purpose of the 'ip nat inside source list' command in Cisco IOS?

Question 29mediumdrag order

Drag and drop the steps of the DHCP DORA process into the correct order, from first to last.

Question 30mediumdrag order

Drag and drop the steps of configuring Dynamic NAT on a Cisco IOS router into the correct order, from first to last.

Question 31mediumdrag order

Full Practice Test →All Objectives

Drag and drop the steps of DHCP snooping operation on a Cisco switch into the correct order, from first to last.

More NAT and DHCP questions available in the full practice test.

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Objective 310.0

NAT and DHCP

350-401 Practice Questions

350-401 NAT and DHCP — Practice Questions

30 questions from this objective

Question 2mediummultiple choice

A network engineer is configuring a Cisco router to provide internet access to a small office using a single public IP address assigned by the ISP. The engineer wants to allow internal hosts to initiate connections to the internet, but also needs to make a web server on the internal network reachable from the internet. The engineer configures a standard access list for NAT and an ip nat inside source list command. However, external users cannot reach the internal web server. What is the most likely cause?

Question 3mediummultiple choice

A network engineer is troubleshooting a DHCP issue on a Cisco router configured as a DHCP server for a VLAN. Clients in the VLAN are able to obtain IP addresses from the DHCP server, but they are not receiving the correct DNS server address. The engineer checks the DHCP pool configuration and sees the dns-server command is configured with the correct IP address. What is the most likely cause of the problem?

Question 4hardmultiple choice

A network engineer is configuring NAT overload (PAT) on a Cisco router to allow multiple internal hosts to share a single public IP address. The engineer uses the command ip nat inside source list 1 interface GigabitEthernet0/0 overload. After testing, internal hosts can access the internet, but some applications fail intermittently. The engineer suspects a NAT issue. What is the most likely cause?

Question 5mediummultiple choice

A network engineer is configuring a Cisco router as a DHCP relay agent to forward DHCP requests from a client VLAN to a centralized DHCP server located in a different subnet. The engineer configures the ip helper-address command on the VLAN interface. However, clients in the VLAN are not receiving IP addresses. The DHCP server is reachable from the router. What is the most likely cause?

Question 6hardmultiple choice

A network engineer is troubleshooting a NAT issue where an internal host cannot establish an SSH session to a remote server on the internet. The engineer checks the NAT translations on the border router and sees that the translation for the host's source IP is present. However, the SSH session times out. The engineer also notices that the remote server's IP is not in the NAT translation table. What is the most likely cause?

Question 7easymultiple choice

A network engineer is configuring a Cisco router to act as a DHCP server for a branch office. The engineer creates a DHCP pool for the 192.168.1.0/24 subnet and configures the default-router, dns-server, and domain-name options. However, clients are able to obtain IP addresses but cannot ping the default gateway. The engineer verifies that the router's interface IP is 192.168.1.1. What is the most likely cause?

Question 8easymultiple choice

A network engineer is configuring NAT on a Cisco router to allow internal hosts to access the internet. The engineer uses the command ip nat inside source list 100 interface GigabitEthernet0/0 overload, where access list 100 permits only the 10.0.0.0/8 network. After testing, hosts in the 10.0.0.0/8 network can access the internet, but hosts in the 172.16.0.0/16 network cannot. The engineer verifies that the 172.16.0.0/16 hosts have connectivity to the router. What is the most likely cause?

Question 9mediummultiple choice

A network engineer is troubleshooting a DHCP issue where a client is not receiving an IP address from a Cisco router configured as a DHCP server. The engineer checks the DHCP pool configuration and sees that the network command is configured with the correct subnet. The engineer also verifies that the ip dhcp excluded-address command is not blocking any addresses. However, the client's DHCP discover message is not reaching the router. What is the most likely cause?

Question 10hardmultiple choice

A network engineer is configuring NAT on a Cisco router to allow internal hosts to access the internet. The engineer uses the command ip nat inside source static tcp 192.168.1.10 80 203.0.113.1 80. After testing, external users can access the internal web server using the public IP. However, internal hosts cannot access the web server using the public IP. What is the most likely cause?

Question 11mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip nat translations

Pro Inside global Inside local Outside local Outside global --- 192.0.2.10 10.0.0.10 --- --- --- 192.0.2.11 10.0.0.11 --- ---

Based on this output, what can be concluded?

Question 12mediummultiple choice

A network engineer runs the following command on Router R2:

R2# debug ip dhcp server events
*Mar  1 00:05:23.123: DHCPD: DHCPDISCOVER received from client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30 on interface GigabitEthernet0/1
*Mar  1 00:05:23.124: DHCPD: Sending DHCPOFFER to client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30 (10.0.0.2)
*Mar  1 00:05:23.125: DHCPD: DHCPREQUEST received from client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30
*Mar  1 00:05:23.126: DHCPD: Sending DHCPACK to client 0063.6973.636f.2d30.3030.302e.3030.3030.2e30.3030.312d.4574.30 (10.0.0.2)

Based on this debug output, what can be concluded?

Question 13hardmultiple choice

A network engineer runs the following command on Router R3:

R3# show ip nat statistics

[Id] ip nat pool POOL1 203.0.113.1 203.0.113.10 netmask 255.255.255.240

refcount 5

Based on this output, what can be concluded?

Question 14mediummultiple choice

A network engineer runs the following command on Router R4:

R4# show ip dhcp binding

Bindings from all pools not associated with VRF:

IP address       Client-ID/              Lease expiration        Type

Hardware address/ User name

10.0.0.10        0063.6973.636f.2d30.    Mar 01 2025 12:00 PM   Automatic
                 3030.302e.3030.3030.
                 2e30.3030.312d.4574.

10.0.0.11        0063.6973.636f.2d30.    Mar 01 2025 12:05 PM   Automatic
                 3030.302e.3030.3030.
                 2e30.3030.312d.4574.

Based on this output, what can be concluded?

Question 15hardmultiple choice

A network engineer runs the following command on Router R5:

R5# show ip nat translations

Pro Inside global Inside local Outside local Outside global udp 192.0.2.20:1234 10.0.0.20:1234 203.0.113.1:53 203.0.113.1:53 tcp 192.0.2.20:5678 10.0.0.20:5678 198.51.100.1:80 198.51.100.1:80

Based on this output, what can be concluded?

Question 16mediummultiple choice

A network engineer runs the following command on Router R6:

R6# show ip dhcp conflict
IP address       Detection method     Detection time         VRF
10.0.0.10        Ping                 Mar 01 2025 10:00 AM   default
10.0.0.15        Gratuitous ARP       Mar 01 2025 10:05 AM   default

Based on this output, what can be concluded?

Question 17mediummultiple choice

A network engineer runs the following command on Router R7:

R7# show ip nat translations verbose

Based on this output, what can be concluded?

Question 18hardmultiple choice

A network engineer runs the following command on Router R8:

R8# show ip dhcp server statistics

Memory usage: 12345 Address pools: 2 Database agents: 0 Automatic bindings: 10 Manual bindings: 2 Expired bindings: 1 Malformed messages: 0

Message Received

BOOTREQUEST    0

DHCPDISCOVER 100 DHCPREQUEST 95 DHCPDECLINE 1 DHCPRELEASE 2 DHCPINFORM 0

Based on this output, what can be concluded?

Question 19hardmultiple choice

A network engineer runs the following command on Router R9:

R9# show ip nat translations

Based on this output, what can be concluded?

Question 20mediummultiple choice

Consider the following configuration snippet: ```

interface GigabitEthernet0/1
 ip address 192.168.1.1 255.255.255.0
 ip nat inside

interface GigabitEthernet0/2
 ip address 203.0.113.1 255.255.255.0
 ip nat outside

ip nat inside source list 1 interface GigabitEthernet0/2 overload
access-list 1 permit 192.168.1.0 0.0.0.255

``` What is the effect of this configuration?

Question 21mediummultiple choice

Examine this DHCP configuration: ```

ip dhcp pool POOL1
 network 10.10.10.0 255.255.255.0

default-router 10.10.10.1 dns-server 8.8.8.8 lease 0 12 !

ip dhcp excluded-address 10.10.10.1 10.10.10.10

``` Which statement is true?

Question 22mediummultiple choice

Given this NAT configuration: ```

interface GigabitEthernet0/0
 ip address 10.0.0.1 255.255.255.0
 ip nat inside

interface GigabitEthernet0/1
 ip address 198.51.100.1 255.255.255.0
 ip nat outside

ip nat inside source static 10.0.0.5 198.51.100.5

``` What is the purpose of this configuration?

Question 23mediummultiple choice

Review the following DHCP relay configuration: ```

interface Vlan10
 ip address 192.168.10.1 255.255.255.0
 ip helper-address 172.16.1.100

``` What is the effect of the 'ip helper-address' command?

Question 24mediummultiple choice

Analyze this NAT configuration: ```

ip nat pool GLOBAL 203.0.113.10 203.0.113.20 netmask 255.255.255.0
ip nat inside source list 1 pool GLOBAL overload
access-list 1 permit 192.168.1.0 0.0.0.255

``` Which statement is correct?

Question 25mediummultiple choice

Examine this DHCP configuration: ```

service dhcp
ip dhcp pool POOL2
 network 10.20.20.0 255.255.255.0

default-router 10.20.20.1 lease infinite ``` What is the effect of the 'lease infinite' command?

Question 26easymultiple choice

What is the default lease time for a DHCP pool in Cisco IOS?

Question 27easymultiple choice

Which type of NAT translates multiple inside addresses to a single outside address using different port numbers?

Question 28mediummultiple choice

What is the purpose of the 'ip nat inside source list' command in Cisco IOS?

Question 29mediumdrag order

Drag and drop the steps of the DHCP DORA process into the correct order, from first to last.

Question 30mediumdrag order

Drag and drop the steps of configuring Dynamic NAT on a Cisco IOS router into the correct order, from first to last.

Question 31mediumdrag order