[CentOS] Slow login to system without internet connection

Ljubomir Ljubojevic office at plnet.rs
Tue Nov 20 20:54:31 UTC 2012

On 11/20/2012 09:47 PM, m.roth at 5-cent.us wrote:
> Ljubomir Ljubojevic wrote:
>> On 11/20/2012 09:25 PM, Les Mikesell wrote:
>>> On Tue, Nov 20, 2012 at 12:48 PM, Ljubomir Ljubojevic <office at plnet.rs>
>>> wrote:
> <snip>
>>>> 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.
> <snip>
>> So the question is: "is there a setting that will reduce that DNS
>> timeout for all running services, maybe like a ping-watchdog that would
>> recognize the problem and skip the reverse-DNS lookup if DNS servers are
>> not reachable?"
> <snip>
> What does it say in /etc/nsswitch: is it dns files, or files dns?

"files dns"

Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

Google is the Mother, Google is the Father, and traceroute is your
trusty Spiderman...
StarOS, Mikrotik and CentOS/RHEL/Linux consultant

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