Network administrator interview questions

The following questions are recommend for candidates aspiring for a network administrator interview.

Interview question 1.

You are a network administrator who have been assigned to setup a DHCP server for an organization for providing IP addresses to multiple networks as in the below topology. How would you proceed?

The DHCP server can be setup on a Windows or Linux platform. Multiple scopes can be setup on the DHCP server corresponding to the IP address for the different networks. IP helper address needs to be configured on router for communication between the DHCP clients residing on different networks and the DHCP server.

Interview question 2.

An internet perimeter Cisco router is being targetted for attacks originating with the source IP addresses as private IP addresses. If you are the network administrator how would you mitigate the threat?

The router can be configure with a standard Access lists, configured as inbound to deny ip packets with source ip addresses as private ip addresses.

Interview question 3.

You are the network admin of an organization which has multiple sites deployed using leased lines. OSPF is the routing protocol which is used on the leased lines for intranet communication. The sites are also configured for DSL based internet connection. The administrator forgot to include the default route configuration on the routers. What type of traffic would be prevented as a consequence of this action?

Default routes are needed for routing internet packets. So internet bound traffic would be dropped.

Interview question 4.

What route entry does the following signify?

Network destination: 192.168.1.1
Netmask: 255.255.255.255

It is a host entry for the host 192.168.1.1

Interview question 5.

In an organization with 10 computers, 1 printer, and 1 Ethernet 48 port switch the network administrator wants to implement a medium security mechanism which would avoid unauthorized systems to access the network. What would be the most viable solution?

Mac-based security can be configured on the switch.

Interview question 6.

A user attempts to login to a web server with random password values for a valid username. The web server does not lock out the user in spite of repeated attempts. What is the vulnerability type the server is exposed to?

Brute force attack

Interview question 7.

A network administrator incorrectly configures the static DNS server IP address on the clients TCP/IP adapter setting. The default gateway of the network which is the internet router has the correct DNS entry in it’s configuration. The clients IP address, subnet mask and the default gateway information is provided by the DHCP server on the router. Would the client be able to browse?

The user would not be able to browse.