RHEL5/6 Interview Questions : Networking

1. What command displays your current interfaces and IP address?

1a. ifconfig

2. What does ifconfig 172.168.1.100 netmask 255.255.255.0 eth1 do?

2a. This command sets the eth1 interface to have a static IP address of
172.168.1.100 with a netmask of 255.255.255.0.

3. What command can you use to test connectivity to another host?

3a. The ping command can be used to verify connectivity to another host.

4. What does it mean if you ping a host and you receive the response Destination Unreachable?

4a. The gateway is incorrectly set, and the subnet of the host you are trying to reach is inaccessible.

5. What is a gateway used for on a network?

5a. A gateway is used as an entry and exit point for a subnet on a network. To contact hosts outside your subnet, you need to pass through a gateway.

6. How would you go about creating a static route?

6a. Use the route command with the add option to create a static route.

7. What command can you use to monitor and troubleshoot network connections?

7a. The tcpdump command is used to monitor network connections on different interfaces.

8. Can you name three utilities that can be used for network or DNS client troubleshooting?

8a. The three utilities are: route, ping, and nslookup.

9. What is the /etc/hosts file used for?

9a. The /etc/hosts file is a local lookup file used to map IP addresses to hostnames if a DNS server isn’t available.