Re: postgres 9.0 - unable to bind to localhost.

Sorry for a late reply, but I had the exact same problem and it was a bug in the Red Hat RPM package upgrade script of the sudo package. This basically means the user running Postgres cannot resolve hostname localhost. Have you tried logging in as the user running Postgres and trying to resolve localhost? In RHEL/Centos you would do this with:

su - postgres

nslookup localhost

A late comment on this one... but I've learnt this lesson the hard way :/
If you want to know what am actual program will get, use "getent hosts <hostname/IP>", that will follow the directions in nsswitch.conf and also use an nscd, if you're running one.

So, if someone (for whatever reason) once put a line
    1.2.3.4 localhost
in your /etc/hosts, the "nslookup" will return what you'd expect (i.e., hopefully ;-), but Postgres will try to open a socket on 1.2.3.4. Bang!

Apart from that:
a) nslookup is deprecated since ages, use "host" or "dig" (well, no, use "getent hosts" ;-)
b) I doubt that all DNS possible servers (M$ ones spring to mind...) will provide answers to "localhost"

Just my 2p...

-- 
Gunnar "Nick" Bluth
RHCE/SCLA

Mobil   +49 172 8853339
Email: gunnar.bluth@pro-open.de
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