TCP Capturing Question

[Neo81]

Hey peeps

Ok I don't know much about this so i'll try and explain it as good as I can..... Ok what I would like to know is if you are say putting in a adsl router on a 192.168.0.X network and you have a server say 192.168.0.1 and the router you put in is setup with the same Ip as what the server is how do you know if there are any ip conficts if you didn't know what the router was setup as .... is there anyway of capturing tcp packets and disecting them to find out where they were comming from and going to??? sorta so you can find out if the router is putting out the same IP as the server but you don't know ..... this is kinda hard to explain .... have a go at that anyways but ask questions if you are unsure what I mean .......

Thanks


Later
NEo81 >:O>

 

[lanceja]

If I understand you correctly you need to know an easy way to see if the server and router are conflicting. I am assuming you have no way of getting to the router configuration. if you did, you could look at the router config.

You could put the router on the network with it powered up. At that point, reboot the server. When the server reboots, it should show that it has a conflict with another user using the same IP address. If you then power down the router and then reboot the server again and get no error, then your router and server are using the same address.

There is a way I believe with nbtstat that can also tell you about IP addresses, but I am still learning that also.

Hopefully this helps.

 

[TheOldMan346]

Neo81,

The basic answer is yes. Any products like NetMon (part of NT Resource Kit, I think) or SnifferPro (Network General) will capture packets and allow you to look at the source and destination addresses. This will not help you resolve the conflict, though. This is a basic issue. Most xDSL routers come with a factory default address. If you suspect a conflict with the server, follow Lanceja's suggestion by rebooting the server. If it does indicate a conflict, you have a choice. You can change the server's address or change the router's address. To change the router, take the server off the network temporarily so you can access the routers configuration web page and adjust the LAN IP address. I'll assume you know how to change the server's address.

There are a number of free/low cost tools to inventory your network and tell you what is out there and how it is set up. The best I've run across so far is LanGuard from

http://www.gfi.com.

It is free for personal use. In order to use ANY of these products, however, you first have to resolve any IP conflicts.

Hope that helps.
The Old Man