Getting "unknown host" on hostname despite adding it to /etc/hosts

Question

I have an Ubuntu server called crow:

$ hostname
crow

But when I try to ping it (from itself), I get unknown host:

$ ping crow
ping: unknown host crow

This is despite explicitly adding crow to /etc/hosts:

$ sudo cat /etc/hosts
127.0.0.1       localhost crow

What am I doing wrong?

Additional info in response to comments:

The hosts line of /etc/nsswitch.conf looks like this:

hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4

Have you rebooted/restarted networking services after making the edit to your `hosts` file? — Pylsa, Feb 02 '11 at 16:50
Modification of hosts file doesn't require restart of network services. — Sameer, Feb 02 '11 at 17:20
where do you ping it, from the server itself or from another machine in the same lan? — Nicola Boccardi, Feb 02 '11 at 19:04
As reference I once had this problem since I by mistake "lost" the s in hosts (in nsswitch.conf). So a faulty nsswitch.conf can cause this problem as well... — Johan, Sep 24 '12 at 13:34

score 5 · Accepted Answer · answered Feb 02 '11 at 19:36

5

Check permissions on /etc/hosts and /etc/nsswitch.conf files. They should be world-readable.

answered Feb 02 '11 at 19:36

rvs

1

Indeed, there should be no need for sudo in `sudo cat /etc/hosts`. – hlovdal Feb 02 '11 at 21:04
And what if they are already world readable, however you still can't ping localhost? – UncleAdam Sep 22 '17 at 21:57

1 Answers1