I am on a university LAN that uses private Class B IPs from 172.31.1.x to 172.31.60.x. I want to know that whether anyone is playing CS on LAN or not, because I am able to see only 172.31.54.x guys from the game options.

Is there any way to find out if anyone's playing across the whole LAN?


1 Answer 1


Your subnet mask is not allowing you to see other subnets on the network.

In routing, the network mask tells your computer what IPs it can see. In your case, your subnet mask is probably set to, which only allows your computer to see IPs on the 172.31.54.x subnet. To tell your computer to see IPs on the 172.31.x.x subnet, you'll have to set your netmask to

This quick guide will tell you how to set your netmask. You'll need to know your IP address and the default gateway assigned to your connection.

  • You'll have to go into the Network and Sharing center: bring up this menu by right clicking your connection icon, then selecting "Open Network and Sharing Center".

Context Menu 1

  • Click on change adapter settings in the left column:

Left Column

  • Right click your connection and select properties:

Context Menu 2

  • Left Click Internet Protocol version 4, then left click properties:

IPv4 Properties

  • Click "Use the following IP address", and input your assigned IP, (ex. the netmask, (Windows should auto complete), your gateway (ex. and finally DNS servers (use the DNS IPs in the screenshot).

Input your settings in these fields

  • You should now be able to find all of those servers on the campus LAN.
  • 2
    The DNS suggested above is Google DNS. More information on that over here: developers.google.com/speed/public-dns/docs/intro
    – user973
    Jan 28, 2013 at 20:38
  • IP and subnet is dynamic, DHCP enabled...Static IP and subnet wont work. Jan 29, 2013 at 2:39
  • This will disable DHCP and force an IP to your computer. Have you tried setting this up? :)
    – Slurpee
    Jan 30, 2013 at 0:04

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