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Long Delay After Password During ssh Login

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Craig Johnson_1
Regular Advisor

Long Delay After Password During ssh Login

I'm seeing a 15-25 second delay after entering my password when logging in via ssh.

11.31 servers. Running Centrify but my account is excluded from it. Telnet shows no delay.

DNS appears to be configured correctly and reverse lookups of the box I'm coming from show no delay or issue.

ssh -vv hostname doesn't show any issue at all. Lots of "it worked".

I tried setting "UseDNS no" in the sshd_config, didn't help.

Any idea?
13 REPLIES
Steven E. Protter
Exalted Contributor

Re: Long Delay After Password During ssh Login

Shalom,


Server being logged into needs an /etc/hosts entry for itself. This takes DNS delay out of the equation.

This is a pretty common problem with HP-UX.

If the inbound server is hostname stevesvr and its ip address is 192.168.0.20 an /etc/hosts entry like:

192.168.0.20 stevesvr stevesvr.yourdomain.com

Will do the trick.
The assumption here is /etc/nsswitch.conf is configured to look at files first. That is industry standard.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Craig Johnson_1
Regular Advisor

Re: Long Delay After Password During ssh Login

This is the server I'm logging into:

# grep b201u005 /etc/hosts
10.10.240.72 b201u005 b201u005.bg.na.jci.com

# ifconfig lan0
lan0: flags=1843
inet 10.10.240.72 netmask ffffffe0 broadcast 10.10.240.95

/etc/nsswitch.conf is set to hosts: files dns
Mel Burslan
Honored Contributor

Re: Long Delay After Password During ssh Login

since you mentioned ssh -vv I am assuming you did the -vvv (triple "v"'s) version. Does the wait happen after you get the

Authentication succeeded (password).

message or before ?

Assuming it happens after, what I would suggest is to put

set -x

line to the beginning of your .profile and .kshrc (assuming you are running ksh, if not, modify accordingly) and try to figure out where the hang-up is.

don't forget the

set +x at the end of each file as well
________________________________
UNIX because I majored in cryptology...
Abid Iqbal
Regular Advisor

Re: Long Delay After Password During ssh Login

Hi,
Please check and report the size of /var/adm/wtmps file.
Matti_Kurkela
Honored Contributor

Re: Long Delay After Password During ssh Login

Check the start-up time of your sshd daemon and compare it to the timestamps of your /etc/resolv.conf, /etc/nsswitch.conf and /etc/hosts files.

If those files have been modified since sshd was started, it is likely sshd is still using the old values.

MK
MK
himacs
Super Advisor
Solution

Re: Long Delay After Password During ssh Login

Craig,

You can null the files /var/adm/wtmps and btmps.
Both files holds the user login related informations.wtmps is for successful logins and btmps is for failed logins.

Regards
himacs
Abid Iqbal
Regular Advisor

Re: Long Delay After Password During ssh Login

Ya, you are right himacs.
The same i asked to check. This will resolve the issue.
Craig Johnson_1
Regular Advisor

Re: Long Delay After Password During ssh Login

Those files are huge:

b201u005:/var/adm > ll *tmps
-rw------- 1 root other 45637392 Apr 4 09:45 btmps
-rw-rw-r-- 1 adm adm 993000564 Apr 5 07:45 wtmps

I'm curious though, why would they affect ssh but not telnet?
Lee Kendrick
Occasional Visitor

Re: Long Delay After Password During ssh Login

wtmps is for SSH / SFTP / SCP and wtmp is for telnet / FTP. Likewise the bad login files, btmps = SSH & btmp = telnet.
James R. Ferguson
Acclaimed Contributor

Re: Long Delay After Password During ssh Login

Hi:

> Lee: wtmps is for SSH / SFTP / SCP and wtmp is for telnet / FTP. Likewise the bad login files, btmps = SSH & btmp = telnet.

No, the files without the "s" at the end are the older versions with only a very short login name character array and a very short hostname character array. These files are to be replaced by their cousins with the "s". Compare the manpage documentation of 'utmp(4)" to 'utmps(4)'.

Regards!

...JRF...
Alzhy
Honored Contributor

Re: Long Delay After Password During ssh Login

There seems to be an unresolved "bug" in sshd on HP-UX 11.31. If you've a large wtmps file - it seems to be affected by it and delays SSH authentication/logins.

Solution:

Trim it down and your issue will be fixed.


dd if=/var/adm/wtmps |gzip >/somewhere/wtmps.gzip

cp /dev/null /var/adm/wtmps

Try your SSH to the server -- it will NOW be fast.

Hakuna Matata.
Craig Johnson_1
Regular Advisor

Re: Long Delay After Password During ssh Login

Nulling them out did the trick! Sped it right up. Thanks!
Flying_Trouser
Occasional Visitor

Re: Long Delay After Password During ssh Login

I know this is an old thread, but, thank you for this solution. 

It has helped me tremendously today with an end user having all sorts of connection issues from an app.