localhost not working, but ip works fine...

[forum query]

Sorry for lack of a better subject header. I've got vncserver running on 
a number of GNu/Linux mahcines in my office, without any problems.

However, I  recently built a GNU/Linux box running CentOS 5.2, that 
seems to be giving me problems.  Start the vncserver using

/usr/bin/vncserver :1

Server is up.

Use SSH Secure Shell to make an ssh2 connection to the server, tunneling 
in as 5901. Fine.

Then, point vncviewer at it - here is where the problems start. Lets 
assume that the new server is called new.server.org

If I use new.server.org:1   in the viewer, connects fine.

But...if I use localhost::1  (or localhost::5901, or a single colon 
instead of double, or any permutation using localhost instead of the 
server name), I can't connect.

Now, it is wroth noting that I've done the exact same thing without any 
problems on my other GNU/Linux boxes - they run Fedora Core 8. Also, all 
the machines are in the same office, so none of the usual issues with 
firewalls etc (i.e., if I can get in on 5901 for one machine, I should 
be able to get in on 5901 on all of them). For some reason I haven't 
sussed out, I can;t get vncserver to accept a localhost connection on my 
CentOS box.

Any ideas where to look? What really puzzles me is why new.server.org:1 
(or new.server.org:5901) works fine, but localhost:1 doesn't.

Thanks in advance...