[CentOS] CentOS 5 ssloooowww when network unavailable

[Bart Schaefer]

On 5/12/07, Jordi Espasa Clofent <sistemes.llistes at intergrid.cat> wrote:
> Making a definitive test is simple: deactive the ntpd service, take off
> the wireless NIC and reboot the system. If the next boot has the
> "normal" speed, you already know what is happens.

It does not seem to be related to ntpd -- or else ntpd is happy with
the addition of the hostname to /etc/hosts.

Something -- I didn't do it directly -- had already added the hostname
to the 127.0.0.1 line in /etc/hosts by the time I got around to
looking there.  I don't know whether it was there before or not, nor
what I did (boot with the wired network plugged in?  Download updates?
The timestamp on /etc/hosts changes every time I reboot, so something
is updating it).  In any case it was not necessary to disable wireless
or deactivate ntpd to get normal response back.

At the same time, if I do anything that requires DNS (like try to ssh
to a remote host), all the symptoms return until the DNS query times
out, at which point all is well again.  So it is DNs's "fault"
somehow.  (Interestingly, even though some warnings from ntpd about
unreachable time servers show up in /var/log/messages, they don't seem
to induce this problem.)