[TriLUG] how do I limit log on off Id to thre IP address

[Aaron S. Joyner]

One way that comes immediately to mind is to require the user to auth 
via certificate, and then setup an RSA or DSA key for the user.  Put a 
from="1.2.3.4, 5.6.7.8, 12.23.34.45" <rest of the key> in the 
.ssh/authorized_hosts2 file, which will allow him to connect, but only 
from those IPs.  Don't give that user access via standard password 
authentication (i.e. change his password to null or to something the 
user doesn't know).  He will have to auth with the certificate, which 
will only be accepted from those IP addresses.  Note: Make sure he 
doesn't have write access to the .ssh/authorized_keys2 file.

Another way would be to wrap up ssh in tcp wrappers via inetd - but 
that's messy, and only logical if that user is the only user who will 
authenticate via ssh (rather unlikely).

For more details on setting up public key auth, consult the man pages 
for sshd and ssh-keygen, or ask again if more info is required.

Aaron J.

Ralph Blach wrote:

> I am running an linux server, and I want to limit a logon  id to
> three ip address. is there any way to do this with sshd?
>
> Thank
>
> Chip