How do you keep users from stealing other user's ip??

[Erik Norgaard]

Mark Jayson Alvarez wrote:
> Hi,
> 
> Ok here's our problems. Mostly pertaining to tracking down who is this 
> user eating up our bandwidth or who is this user flooding our network.
> 
> 1. Users when they want to plug a machine to the network... let's say 
> their own testbeds, they will choose whatever ip they want possibly 
> stealing used ip's.
> 
> 2. Users workstations are mixed Windows and *nixes. Most windows 
> machines are getting infected with worm from time to time... Some of 
> them are not so skillful enough to clean their own workstations. Given 
> an unmanaged ip allocation, it would also be hard to trace which 
> machines are causing the network congestion.
> 
> 3. Some users with public workstations and testbeds are eating up 
> bandwidth through file sharing...Still hard to trace this without proper 
> ip allocation management.

If the problem is that users choose occupied ips by accident rather than 
by bad will, then use dhcp. Windows users and novices will thank you for 
not having to deal with the configuration and you can say "just plug it 
in and it works".

If you want to make people aware of what it means to be on the network, 
register their hosts with mac address and have them sign a paper with 
your AUP. Track changes with arpwatch.

Assign a segment of your address space to testbeds, tell people who want 
to experiment that they choose an ip in that segment. That segment 
should be blocked or only have access to limited services such as dns, 
ftp and http.

Block all access to port 25 on internet to make sure that mail is sent 
through your mailserver. Require authentication for smtp. This means 
that at least you won't spread the viruses that infect the windows clients.

Cheers, Erik

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