If you are using some other protocol than AFP, then you need to specify it.

When you just type in the address/IP of the server, the connect to dialog ASSUMES the AFP protocol.

However, if you put 'nfs://' or 'smb://', that should give you the shares after specifying your login details.

Say the server's IP is 172.0.0.10.

Go>Connect to Server...

The put in "smb://172.0.0.10"

Then it asks for the login details, and will then give you the list of shares you have access to just like normal with an AFP (Apple Filing Protocol) server.

Any linux server that hosts machines other than linux workstations SHOULD have SMB enabled, and Macs can connect to those shares.

Sorry for the late response!