Forbid >2 login from the same IP

[gpayo]

Hello all,

I've a server with a common login (with "common" I mean several users use the same login). What I want to forbid is a "second" login from the same IP address.

I'm not talking about wrong logins attempts or anything related to that.

I mean:

Jane, IP: 111.111.111.111 -> Logins ok to my server.

Jane's brother, IP: 111.111.111.111 -> tries to login in server, but he can't.

Is this possible?

Cheers

[unspawn]

What kind of logins are you talking about? Web site sessions? FTP? SSH? Or (${deities} forfend!) telnet?

I'm asking this (apart from common logins not exactly being a security best practice) because the network stack doesn't have a concept of "logins" but services do. I mean you'll unlikely "solve" this with say a wee bit of iptables magic.