Comment 52 for bug 574152

Completely unsolicited advice as I was searching for another bug: what's /etc/nsswitch.conf look like? What happens if you change the "hosts" line to "hosts: files dns"? and change "passwd", "group" and "shadow" all to "compat" alone?

The symptoms you describe are identical to what I experienced a few years ago with a broken /etc/nsswitch.conf--the file had some questionable settings involving Kerberos and LDAP.