connectivity problem

Hi Everybody,

I am having difficulty connecting to postgres service from
a remote machine on the network.

My postgres (8.3.6, on Linux) is running on a machine
(vixen) and I would like to connect to it from another host.

The host (named blitzen, runs linux as well) appears in
pg_hba.conf of vixen as:
host canon all 172.16.1.106/32 md5 # blitzen

and when I issue "psql canon" from blitzen, it complains as:
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

I think the complaint means that blitzen is not running
postmaster/postgres.

The host id of server (vixen) is 107 and I have no problem
ssh'ing from blitzen:

[tsakai(at)blitzen Gallo]$ nslookup vixen
Server: 127.0.0.1
Address: 127.0.0.1#53

Non-authoritative answer:
Name: vixen.egcrc.org
Address: 172.16.1.107

[tsakai(at)blitzen Gallo]$ ssh -l tsakai 172.16.1.107
Last login: Fri Apr 10 12:16:57 2009 from 05-141.egcrc.org
[tsakai(at)vixen ~]$

How can I get a response from postmaster via psql from a
client machine? I would appreciate any help. Thank you.

Regards,

Tena Sakai
tsakai(at)gallo(dot)ucsf(dot)edu