[OpenIndiana-discuss] Slow ssh login?

Richard Elling richard.elling at richardelling.com
Fri Oct 19 23:02:34 UTC 2012

On Oct 19, 2012, at 3:51 PM, "Dan Swartzendruber" <dswartz at druber.com> wrote:

> Hi, all.  I've got an issue that is bugging me.  I've got an OI 151a7 VM and
> ssh to it takes 15 seconds or so, then I get a prompt.  It's not the usual
> reverse dns or gssapi stuff, since my backup node is also OI 151a7 and it
> responds instantly to the ssh request.

15 seconds is a magic number -- the default timeout for a DNS lookup.
Use getent to verify that lookups (forward and reverse) are fast. Use nscd -i
to make sure the cached name lookups are flushed.

Another quick test, if the first ssh takes a while, but soon afterwards a second
completes quickly, then the nscd cache is working properly.
 -- richard

>  Google has not turned up anything
> useful except for the usual suspects that are innocent in this case.  The
> only hint I can see is if I give '-v' on the client, I see this:
> OpenSSH_5.9p1 Debian-5ubuntu1, OpenSSL 1.0.1 14 Mar 2012
> debug1: Reading configuration data /etc/ssh/ssh_config
> debug1: /etc/ssh/ssh_config line 19: Applying options for *
> debug1: Connecting to nas [] port 22.
> debug1: Connection established.
> debug1: identity file /home/dswartz/.ssh/id_rsa type -1
> debug1: identity file /home/dswartz/.ssh/id_rsa-cert type -1
> debug1: identity file /home/dswartz/.ssh/id_dsa type -1
> debug1: identity file /home/dswartz/.ssh/id_dsa-cert type -1
> debug1: identity file /home/dswartz/.ssh/id_ecdsa type -1
> debug1: identity file /home/dswartz/.ssh/id_ecdsa-cert type -1
> debug1: Remote protocol version 2.0, remote software version Sun_SSH_1.5
> debug1: no match: Sun_SSH_1.5
> debug1: Enabling compatibility mode for protocol 2.0
> debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1
> debug1: SSH2_MSG_KEXINIT sent
> (the delay is here)
> debug1: SSH2_MSG_KEXINIT received
> debug1: kex: server->client aes128-ctr hmac-md5 none
> debug1: kex: client->server aes128-ctr hmac-md5 none
> debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
> debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
> debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
> debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
> debug1: Server host key: RSA 8c:78:a0:17:6b:17:1b:bf:83:69:a3:bf:59:df:18:07
> debug1: Host 'nas' is known and matches the RSA host key.
> debug1: Found key in /home/dswartz/.ssh/known_hosts:9
> debug1: ssh_rsa_verify: signature correct
> debug1: SSH2_MSG_NEWKEYS sent
> debug1: expecting SSH2_MSG_NEWKEYS
> debug1: SSH2_MSG_NEWKEYS received
> debug1: Roaming not allowed by server
> debug1: SSH2_MSG_SERVICE_ACCEPT received
> debug1: Authentications that can continue:
> publickey,password,keyboard-interactive
> debug1: Next authentication method: publickey
> debug1: Trying private key: /home/dswartz/.ssh/id_rsa
> debug1: Trying private key: /home/dswartz/.ssh/id_dsa
> debug1: Trying private key: /home/dswartz/.ssh/id_ecdsa
> debug1: Next authentication method: keyboard-interactive
> Any thoughts where to look?  It's got to be something that is different
> between the two OI hosts, but offhand, I'm not sure where to look.
> Thanks...
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Richard.Elling at RichardElling.com

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