[CentOS] how to debug ssh slow connection issues.

Jason Pyeron jpyeron at pdinc.us
Fri May 23 18:24:36 UTC 2008



> -----Original Message-----
> From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On
> Behalf Of Paul Heinlein
> Sent: Friday, May 23, 2008 2:17 PM
> 
> On Fri, 23 May 2008, Jason Pyeron wrote:
> 
> > debug3: Normalising mapped IPv4 in IPv6 address
> > debug3: Trying to reverse map address 192.168.1.80.
> >
> > paused 7 seconds
> 
> Here, obviously, is part of the problem. Your name service isn't
> answering reverse lookups for your LAN addresses -- or it least it
> isn't answering them in a timely manner. Fixing that, either through
> DNS or /etc/hosts, will help a bunch.

[root at 192.168.1.21 ~]# date && host 192.168.1.80  && date && host
host80.1.internal.pdinc.us && date Fri May 23 13:55:52 EDT 2008
80.1.168.192.in-addr.arpa domain name pointer host80.1.internal.pdinc.us.
Fri May 23 13:55:52 EDT 2008
host80.1.internal.pdinc.us has address 192.168.1.80 Fri May 23 13:55:52 EDT
2008
[root at 192.168.1.21 ~]#

Hmmm, does not take 7 seconds.



> 
> > debug1: do_pam_account: called
> >
> > pause 7 seconds
> >
> > debug3: PAM: do_pam_account pam_acct_mgmt = 0 (Success)
> 
> This delay puzzles me. Are you using LDAP as an authentication
> backend? If so, reverse-mapping failure may be the issue here, too.

NIS. But the delay is constant regardless of the user being in the local
/etc/passwd or NIS.  Further on the local prompt "id user" works just fine.




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