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

Renato de Oliveira Diogo renato.diogo at gmail.com
Tue Mar 31 13:27:49 UTC 2009


You can disable DNS check in your ssh server.
In the /etc/ssh/sshd_config you set "UseDNS" to "no"
===
UseDNS no
===

[]s
________________________________________________
Renato de Oliveira Diogo

Bacharel em Ciência da Computação
UNESP - Bauru

LPIC1 - Linux Professional Institute Certification - Nível 1

renato.diogo at gmail.com
renato.diogo at yahoo.com.br



On Tue, Mar 31, 2009 at 08:22, Jim Perrin <jperrin at gmail.com> wrote:
> 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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