If you can see this check that

next section prev section up prev page next page

Network Configuration

Linux Networking
User:
Password:
In this tutorial you will encounter a number of Linux commands that you may not have seen before, use the man command on your system to find out more about any Linux command that you are unsure of.

Question 1: Network broadcast

What is the broadcast address for your network connection?

Enter an ip :

Tests - not attempted
Broadcast Address UNTESTED

Question 2: ip route

Using the ip command, what is the scope type of the first line of the route table main? (Hint: to display the tables available use the command 'ip rule show'. To show a specific table use 'ip route show table <name>' )

Enter a scope type:

Tests - not attempted
Scope Type UNTESTED

Question 3: Listening servers

How many programs are listening on TCP sockets on your machine. Hint: the netstat command will help you here.

Number of TCP listeners:

Tests - not attempted
TCP Listeners UNTESTED

Question 4: Listening processes

What is the PID of the process which is listening on UDP port 111 (sunrpc). Hint: the netstat command will help you here.

PID of listener:

Tests - not attempted
PID of Listener UNTESTED

Question 5: Your proxy connection

When you connected to linuxzoo.net via telnet or ssh, it was forwarded from 10.200.0.1 to your machine's telnet or ssh server using a proxy. Find the port number on the 10.200.0.1 end of one of these proxy connections and enter it below. Hint: again try the netstat command ...

10.200.0.1 proxy port:

Tests - not attempted
Check Proxy Port UNTESTED

Question 6: Traceroute: hop count

In order for your virtual machine to reach the internet, it's packets travels through a number of virtual networks. The final network node is 10.200.0.1.

Using traceroute, find out how many hops it takes to reach 10.200.0.1.

Num of hops:

Tests - not attempted
Count the hops UNTESTED

Question 7: nmap: Open ports

Use nmap to analyse the ports open on 10.200.0.1. As the nmap command can take quite a while to run, restrict your scan to the open tcp ports between port numbers 50 to 80 inclusive. List the open port numbers you find with spaces between them in the box below (e.g. if ports 50 and 60 are open, the answer is "50 60"). The numbers in your list must be sorted (smallest number first).

Open ports:

Tests - not attempted
Identify of open ports on 10.200.0.1 UNTESTED

Question 8: tcpdump and traceroute

The tcpdump command allows us to capture all or some of the network traffic on a particular network device. In this question use the tcpdump command to capture the behaviour of traceroute.

The traceroute command send packets with short time to live packets (ttl) and waits for a particular ICMP response to indicate that the time has expired. Use tcpdump and traceroute together to find out the ICMP packet id which does this.

Capturing packets sucessfully can be tricky, especially since you have to use the same network to talk to your machine, and you dont want to capture that too... Therefore consider the following commands to perform the capturing. 

prompt> tcpdump -i eth0 not port 23 and not port 22 > /tmp/log &
[1] 3123
prompt> traceroute 10.200.0.1
...blah...blah
...blah...blah
prompt> kill -1 %1
[1]+ Done ....
prompt>

Now, look at the contents of /tmp/log and enter in the box below the ICMP id involved in traceroute knowing that the ttl has been exceeded.

ICMP id used by traceroute:

Tests - not attempted
Check the ICMP id UNTESTED
Tutlinks: intro1 intro2 wildcard permission pipe vi essential admin net fwall DNS diag Apache1 Apache2 MySQL1 MySQL2
Useful: Quiz Forums
Site Links:XMLZoo ActiveSQL ProgZoo SQLZoo