LPIC-2 Practice Test 6 — 10 Questions

Question 1

The server is unable to communicate with hosts on the 192.168.2.0/24 network. Based on the exhibit, what is the most likely cause?

Accepted Answer

The interface has no default gateway configured.. The exhibit shows the interface has an IP address of 192.168.1.10/24 and a default gateway of 0.0.0.0, meaning no default gateway is configured. Without a default gateway, the host cannot route packets to the 192.168.2.0/24 network because that network is not directly connected (it is on a different subnet), and the host has no route to forward traffic beyond its local link. The `route -n` output would confirm the absence of a gateway entry, which is the most likely cause of the communication failure.

Answer

The interface has a duplicate IP address.

Answer

The hardware address is corrupted.

Answer

The subnet mask is incorrect.

Question 2

Traffic from the 10.1.1.0/24 subnet is seen leaving through eth1 as intended, but reply traffic from the internet never comes back. What is the most likely cause?

Accepted Answer

The kernel parameter net.ipv4.conf.all.rp_filter is set to 1.. When `net.ipv4.conf.all.rp_filter` is set to 1, the kernel performs strict reverse path filtering. This means the kernel checks whether the source address of incoming packets can be reached via the interface they arrived on. If reply traffic from the internet arrives on an interface (e.g., eth0) that does not have a route back to the original source subnet (10.1.1.0/24) through that same interface, the kernel drops the packet. This is the most likely cause because the outbound traffic leaves via eth1, but the reply comes back on a different interface, triggering the rp_filter check and causing the reply to be silently discarded.

Answer

The ip rule priority is not set, causing it to be overridden.

Answer

The default route in table 200 points to 172.16.0.1 which does not have a route back to 10.1.1.0/24.

Answer

The router does not have a route back to 10.1.1.0/24 via eth0.

Question 3

An administrator is troubleshooting IPv6 connectivity on a Linux host. The host has an IPv6 address configured on eth0, but cannot ping6 the default gateway. The output of 'ip -6 route show' shows a default route via fe80::1 dev eth0. Which tool should be used to verify that the neighbor discovery process is working?

Accepted Answer

ip neigh show. The 'ip neigh show' command displays the neighbor cache (equivalent to ARP table for IPv6), which is populated by the Neighbor Discovery Protocol (NDP). Since the default gateway is a link-local address (fe80::1), the host must have resolved the gateway's MAC address via NDP before it can send packets. If the neighbor entry is missing or incomplete (e.g., STALE or FAILED), it indicates that the neighbor discovery process is not working, which would explain the ping failure.

Answer

tcpdump -i eth0 icmp6

Answer

traceroute6

Answer

ndp -n

Question 4

A Linux router is experiencing asymmetric routing issues. The network has two internet connections (ISP1 and ISP2) with default routes. The administrator wants to ensure that traffic originating from a specific source IP uses ISP1 for both incoming and outgoing packets. Which ip rule configuration achieves this?

Accepted Answer

ip rule add from 10.0.0.10 table isp1; ip route add default via 1.1.1.1 table isp1; sysctl -w net.ipv4.conf.all.rp_filter=0. It creates a policy routing rule that matches traffic from source IP 10.0.0.10 and directs it to a custom routing table named 'isp1', which contains a default route via ISP1's gateway (1.1.1.1). Additionally, disabling reverse path filtering (rp_filter=0) is essential to allow asymmetric routing — without it, the kernel would drop return packets arriving via a different interface than the one used for outgoing traffic, which is exactly the scenario in asymmetric routing.

Answer

ip rule add from 10.0.0.10 to 0/0 table isp1; ip route add default via 1.1.1.1 table isp1; ip rule add to 10.0.0.10 table isp1

Answer

ip rule add from 10.0.0.10 table isp1; ip route add default via 1.1.1.1 table isp1

Answer

ip rule add from 10.0.0.10 table isp1; ip route add default via 1.1.1.1

Question 5

A system administrator wants to allow incoming SSH connections from only the 192.168.1.0/24 network on a Linux server. Which iptables rule accomplishes this?

Accepted Answer

iptables -A INPUT -p tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT. It appends a rule to the INPUT chain that matches TCP traffic destined for port 22 (SSH) from source IP range 192.168.1.0/24 and accepts it. This restricts incoming SSH connections to only the specified network, which is the intended behavior.

Answer

iptables -A INPUT -p tcp --dport 22 -d 192.168.1.0/24 -j ACCEPT

Answer

iptables -A INPUT -p udp --dport 22 -s 192.168.1.0/24 -j ACCEPT

Answer

iptables -A FORWARD -p tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT

Question 6

A network administrator is configuring source-based routing. They have created a new routing table and added a default route. They then run: ip rule add to 10.0.0.0/24 lookup 100. Traffic from 10.0.0.0/24 still uses the main table. What is the problem?

Accepted Answer

The rule uses 'to' instead of 'from' to match the source subnet.. The `ip rule add to 10.0.0.0/24 lookup 100` command uses the `to` keyword, which matches the destination address, not the source address. For source-based routing, you must use the `from` keyword to match the source subnet. Since the rule matches destination 10.0.0.0/24 instead of source, traffic originating from 10.0.0.0/24 is not matched by this rule and continues to use the main routing table.

Answer

The rule is not persistent.

Answer

The rule priority is too high.

Answer

The routing table 100 does not have a default route.

Question 7

A system administrator wants to combine two 1 Gbps Ethernet interfaces into a single logical bonded interface to increase throughput and provide redundancy. Which mode of bonding will provide both load balancing and fault tolerance without requiring switch configuration?

Accepted Answer

mode 6 (balance-alb). Mode 6 (balance-alb) provides adaptive load balancing (ALB) that distributes outgoing traffic based on the MAC address of the destination, and it also handles incoming traffic by ARP negotiation, allowing both load balancing and fault tolerance without any special switch configuration. Unlike other modes that require switch support (e.g., IEEE 802.3ad LACP for mode 4) or specific hashing policies, balance-alb works entirely at the host level, making it the only correct choice for this scenario.

Answer

mode 2 (balance-xor)

Answer

mode 1 (active-backup)

Answer

mode 0 (balance-rr)

Question 8

Which THREE of the following are correct statements about LVM thin provisioning? (Select THREE)

Accepted Answer

Snapshots of thin volumes use the same pool.. LVM thin provisioning uses a shared thin pool to store data for all thin volumes and their snapshots. When a snapshot of a thin volume is created, it does not allocate separate physical storage; instead, it references the same thin pool, allowing efficient space usage and copy-on-write semantics.

Answer

A thin pool can be resized smaller without data loss.

Answer

Thin volumes must be created before the thin pool.

Question 9

Which of the following commands creates a new network namespace named 'test'?

Accepted Answer

ip netns add test. The correct command to create a new network namespace named 'test' is 'ip netns add test'. The 'ip netns' command is part of the iproute2 suite and is the standard tool for managing network namespaces in Linux. The 'add' subcommand creates a new namespace by binding it to a mount point under /var/run/netns/.

Answer

netns add test

Answer

network namespace add test

Answer

ip netns create test

Question 10

Which TWO conditions must be met for a Linux bridge to forward traffic between its ports?

Accepted Answer

The bridge has at least two ports added.. A Linux bridge requires at least two ports to forward traffic; a bridge with only one port cannot forward frames between interfaces. Option C is correct because the bridge kernel module must be loaded (e.g., via `modprobe bridge`) to provide the bridging functionality; without it, bridge operations are impossible.

Answer

The bridge has an IP address.

Answer

The interfaces are in promiscuous mode.

Answer

Spanning Tree Protocol is disabled.