EH-Net

Well, it used to depend on what chat service/client you were using and how you're chatting with the friend.

I don't use gmail for chatting, but knowing the way Google operates, I'd venture to guess that you probably cannot get the IP address.

For things like AIM (and I think this has changed since), the way to obtain the IP address of the person you're chatting with was to make a 'direct connection' which basically bypassed the AIM chat server and connected client-to-client. This would obviously open up a connection directly to the IP of the person you're chatting with.

So, the simple answer is: no.

As the connection is typically: you <-> chat server <-> friend
Unless you can direct connect: you <-> friend

Hope that helps. Maybe someone else will have some further insight.

BillV

Sending a file through MSN used to make a direct connection. Not sure if that works anymore. You could use social engineering. ie. intice the friend to visit a php page that will grab their http headers.

Or if the chat room allows posting of remote images, you could use the method I have outlined in the post called 'is this a vulnerability?'.

If it works similar to how Y! messenger works (or used to) you could like they said attempt to make a direct connection. You could do this by inviting the user to your web cam, inviting the user to photo sharing, sending a file, etc. After doing that you could run a netstat command and it's typical you'd see their IP Address next to the port that the messenger service uses. For Y! My Guess Would Be 5050, so I'd run : (Doing it as if your on a windows box)
netstat -an |find "5050"
In hope of finding my victim IP Address. Good luck though, your best bet would be to do it like how ethicalhacker said it, send them to a site.