[CentOS] CentOS5U2 waiting too long when ssh login to other linux servers

Jim Perrin jperrin at gmail.com
Tue Mar 31 12:22:52 UTC 2009


On Tue, Mar 31, 2009 at 7:00 AM, Ryan J M <sync.jma at gmail.com> wrote:
> The waiting time is about 50s on my CentOS box now. "yum remove
> openssh* "and "yum  install openssh*" can't make it right. "mv
> ~/.ssh{,.bak}" not works either.
> Here comes my tcpdump log, I am not an expert on SSH, Can anyone here
> get me out of this?

Usually ssh slowness is attributed to DNS problems with reverse
lookups. You give ssh a host name to connect to, and it does a query
to find the ip, then a reverse to make sure that the ip is who it
claims to be. If there are no records, ssh will happily wait for the
query to time out before proceeding. This is usually where people
complain about slowness on home networks or in some hosted
environments that aren't set up 100% correctly. The proper fix is to
correct the DNS issue. Some folks simply hand jam an entry into
/etc/hosts, or dive into the sshd_config and disable the check. How
you resolve this is up to you.



-- 
During times of universal deceit, telling the truth becomes a revolutionary act.
George Orwell


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