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Pete French

2003-Sep-22 07:54 UTC

Very slow SSh since upgrading machines to RELENG_4_8

Due to the recent OpenSSh security alert I have upgraded all our
machines to 4.8-RELEASE-p7 (they were running 4.6.2 before).

We have two set of machines,- some here on 172.16.0.0 and some
in Jersey on 172.19.0.0 I can ssh from the machines here to the
machines in Jersey as normal, and I can also ssh back the same way.

but if I try and ssh between two machines in Jersey then ssh pauses for
a considerable length of time before letting me in. By "considerable"
I mean over a minute.

Preseumably the far end is trying to do something and then timing out,
but the question is *what* is it doing and how do I fix it ? Also
why did this only change when I upgraded ?

The output from ssh -v is shown below to show the point at which is
is pausing... hope somebody can help here as its causing a lot of
inconvenience and a few real problems as it also affects rsync.

help!

-pcf.

---------------


bash-2.05a$ ssh -v websvr04
OpenSSH_3.5p1 FreeBSD-20030917, SSH protocols 1.5/2.0, OpenSSL 0x0090701f
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Rhosts Authentication disabled, originating port will not be trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to websvr04 [172.19.84.0] port 22.
debug1: Connection established.
debug1: identity file /home/webadmin/.ssh/identity type -1
debug1: identity file /home/webadmin/.ssh/id_rsa type -1
debug1: identity file /home/webadmin/.ssh/id_dsa type 2
debug1: Remote protocol version 1.99, remote software version OpenSSH_3.5p1
FreeBSD-20030917
debug1: match: OpenSSH_3.5p1 FreeBSD-20030917 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.5p1 FreeBSD-20030917
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 120/256
debug1: bits set: 1585/3191
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'websvr04' is known and matches the DSA host key.
debug1: Found key in /home/webadmin/.ssh/known_hosts:5
debug1: bits set: 1604/3191
debug1: ssh_dss_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT

...and here it pauses for 60 seconds or so...

debug1: authentications that can continue:
publickey,password,keyboard-interactive
debug1: next auth method to try is publickey
debug1: try privkey: /home/webadmin/.ssh/identity
debug1: try privkey: /home/webadmin/.ssh/id_rsa
debug1: try pubkey: /home/webadmin/.ssh/id_dsa
debug1: input_userauth_pk_ok: pkalg ssh-dss blen 434 lastkey 0x806d0e0 hint 2
debug1: read PEM private key done: type DSA
debug1: ssh-userauth2 successful: method publickey
debug1: channel 0: new [client-session]
debug1: send channel open 0
debug1: Entering interactive session.
debug1: ssh_session2_setup: id 0
debug1: channel request 0: pty-req
debug1: channel request 0: shell
debug1: fd 3 setting TCP_NODELAY
debug1: channel 0: open confirm rwindow 0 rmax 32768
Last login: Mon Sep 22 15:42:27 2003 from turpentine
Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994
        The Regents of the University of California.  All rights reserved.

Pete French

2003-Sep-22 08:41 UTC

head link

Very slow SSh since upgrading machines to RELENG_4_8

> Is your client listed in DNS?
> That can be a reason...
No, but each machine is listed in the others /etc/hosts file. They
dont have DNS entries because they are internal machines.

-pcf.

Gavin Atkinson

2003-Sep-22 08:45 UTC

head link

Very slow SSh since upgrading machines to RELENG_4_8

> -----Original Message-----
> From: owner-freebsd-stable@freebsd.org 
> [mailto:owner-freebsd-stable@freebsd.org] On Behalf Of Pete French
> Sent: 22 September 2003 15:54
> 
> but if I try and ssh between two machines in Jersey then ssh pauses
for> a considerable length of time before letting me in. By
"considerable"
> I mean over a minute.
> 
> Preseumably the far end is trying to do something and then timing out,
> but the question is *what* is it doing and how do I fix it ? Also
> why did this only change when I upgraded ?
This sounds suspiciously like DNS timing out. I seem to remember this is
due to the fact the default config of sshd now enables privilege
seperation. sshd chroots into /var/empty and therefore can't access
/etc/hosts, /etc/nsswitch.conf, /etc/resolv.conf etc.

See, for example,
http://www.freebsd.org/cgi/getmsg.cgi?fetch=509623+513499+/usr/local/www
/db/text/2003/freebsd-stable/20030323.freebsd-stable

Gavin

Dmitry Agafonov

2003-Sep-22 11:01 UTC

head link

Very slow SSh since upgrading machines to RELENG_4_8

Hi!

Is your client listed in DNS?
That can be a reason...

Pete French wrote:
>Due to the recent OpenSSh security alert I have upgraded all our
>machines to 4.8-RELEASE-p7 (they were running 4.6.2 before).
>
>We have two set of machines,- some here on 172.16.0.0 and some
>in Jersey on 172.19.0.0 I can ssh from the machines here to the
>machines in Jersey as normal, and I can also ssh back the same way.
>
>but if I try and ssh between two machines in Jersey then ssh pauses for
>a considerable length of time before letting me in. By
"considerable"
>I mean over a minute.
>
>Preseumably the far end is trying to do something and then timing out,
>but the question is *what* is it doing and how do I fix it ? Also
>why did this only change when I upgraded ?
>
>The output from ssh -v is shown below to show the point at which is
>is pausing... hope somebody can help here as its causing a lot of
>inconvenience and a few real problems as it also affects rsync.
>
>help!
>
>-pcf.
>
>---------------
>
>
>bash-2.05a$ ssh -v websvr04
>OpenSSH_3.5p1 FreeBSD-20030917, SSH protocols 1.5/2.0, OpenSSL 0x0090701f
>debug1: Reading configuration data /etc/ssh/ssh_config
>debug1: Rhosts Authentication disabled, originating port will not be
trusted.
>debug1: ssh_connect: needpriv 0
>debug1: Connecting to websvr04 [172.19.84.0] port 22.
>debug1: Connection established.
>debug1: identity file /home/webadmin/.ssh/identity type -1
>debug1: identity file /home/webadmin/.ssh/id_rsa type -1
>debug1: identity file /home/webadmin/.ssh/id_dsa type 2
>debug1: Remote protocol version 1.99, remote software version OpenSSH_3.5p1
FreeBSD-20030917
>debug1: match: OpenSSH_3.5p1 FreeBSD-20030917 pat OpenSSH*
>debug1: Enabling compatibility mode for protocol 2.0
>debug1: Local version string SSH-2.0-OpenSSH_3.5p1 FreeBSD-20030917
>debug1: SSH2_MSG_KEXINIT sent
>debug1: SSH2_MSG_KEXINIT received
>debug1: kex: server->client aes128-cbc hmac-md5 none
>debug1: kex: client->server aes128-cbc hmac-md5 none
>debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
>debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
>debug1: dh_gen_key: priv key bits set: 120/256
>debug1: bits set: 1585/3191
>debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
>debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
>debug1: Host 'websvr04' is known and matches the DSA host key.
>debug1: Found key in /home/webadmin/.ssh/known_hosts:5
>debug1: bits set: 1604/3191
>debug1: ssh_dss_verify: signature correct
>debug1: kex_derive_keys
>debug1: newkeys: mode 1
>debug1: SSH2_MSG_NEWKEYS sent
>debug1: waiting for SSH2_MSG_NEWKEYS
>debug1: newkeys: mode 0
>debug1: SSH2_MSG_NEWKEYS received
>debug1: done: ssh_kex2.
>debug1: send SSH2_MSG_SERVICE_REQUEST
>debug1: service_accept: ssh-userauth
>debug1: got SSH2_MSG_SERVICE_ACCEPT
>
>...and here it pauses for 60 seconds or so...
>
>debug1: authentications that can continue:
publickey,password,keyboard-interactive
>debug1: next auth method to try is publickey
>debug1: try privkey: /home/webadmin/.ssh/identity
>debug1: try privkey: /home/webadmin/.ssh/id_rsa
>debug1: try pubkey: /home/webadmin/.ssh/id_dsa
>debug1: input_userauth_pk_ok: pkalg ssh-dss blen 434 lastkey 0x806d0e0 hint
2
>debug1: read PEM private key done: type DSA
>debug1: ssh-userauth2 successful: method publickey
>debug1: channel 0: new [client-session]
>debug1: send channel open 0
>debug1: Entering interactive session.
>debug1: ssh_session2_setup: id 0
>debug1: channel request 0: pty-req
>debug1: channel request 0: shell
>debug1: fd 3 setting TCP_NODELAY
>debug1: channel 0: open confirm rwindow 0 rmax 32768
>Last login: Mon Sep 22 15:42:27 2003 from turpentine
>Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994
>        The Regents of the University of California.  All rights reserved.
>
>
>
>_______________________________________________
>freebsd-stable@freebsd.org mailing list
>http://lists.freebsd.org/mailman/listinfo/freebsd-stable
>To unsubscribe, send any mail to
"freebsd-stable-unsubscribe@freebsd.org"
>
>
>  
>

freebsd stable - Sep 2003 - Very slow SSh since upgrading machines to RELENG_4_8

Very slow SSh since upgrading machines to RELENG_4_8

Very slow SSh since upgrading machines to RELENG_4_8

Very slow SSh since upgrading machines to RELENG_4_8

Very slow SSh since upgrading machines to RELENG_4_8