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My hosts file is being ignored, apparently.

It contains: localhost.localdomain localhost mydomain.com nowhere

If I ping localhost or 'nowhere', I get an 'unknown host' error. If I ping mydomain.com, ping succeeds, but it reports the internet ip address (from an outside name server) for mydomain.com.

The server is running ubuntu hardy. Is there a way disable (and reenable) the /etc/hosts file?

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4 Answers 4

up vote 8 down vote accepted

I found the problem.

The /etc/hosts file had overly restrictive permissions -rw------ (I believe that is 600 octal). Changing that to mode 644 fixed the problem.

My tests with ping were done with ordinary priv, and the hosts file was unreadable. My original problem was getting postgresql to startup properly; it starts with root privilege, but apparently sheds priv before starting its child processes for autovacuum and such, so by the time it needed a domain resolved, it could not read the hosts file.

Thanks to everybody who replied. It has been enlightening.

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You just saved me a heap of time. Thank you :) –  Gerry Feb 19 '12 at 16:18

Check /etc/nsswitch.conf

You should have a line like:

hosts: files dns

if the "files" part is missing, /etc/hosts won't be checked.

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the hosts file is strange sometimes on some distrib, try put all localhost alias in the same line

like this : localhost.localdomain localhost mydomain.com nowhere
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You just saved my life man!!! Brilliant! Wasted two hours till i saw this –  In God I Trust Sep 6 '12 at 18:12

Not sure of the specifics of ubuntu, but it seems like your local resolver isn't configured properly. You should try man resolv.conf or man nslookup to see how to configure it.

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