[CentOS] Slow login to system without internet connection

Tue Nov 20 20:25:17 UTC 2012
Les Mikesell <lesmikesell at gmail.com>

On Tue, Nov 20, 2012 at 12:48 PM, Ljubomir Ljubojevic <office at plnet.rs> wrote:
> Now, when there was power failure (works on the transformer there), I
> lost my internet connection, but router and wireless routers for the
> rest of my towers were accessible. SSH logins to any of them is instant.
> But when I tried to login to my server, it was not instantenous, and I
> think it was 15+, maybe even 30+ seconds (I forgot to time it) from
> start of ssh command to password prompt. It is in-house connection, so
> there is nothing to traceroute.

Most server apps will do a reverse-DNS lookup, if only to log the name
for the connection, some will try an ident query for the user at the
other end of the socket.   A 30+ second delay is a pretty sure sign
that one or more of the DNS servers in your resolv.conf did not
respond.  Running a local nameserver with a dummy local domain is one
way to fix it, but just putting all your local systems in the
/etc/hosts file will work too.

   Les Mikesell
       lesmikesell at gmail.com