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Old 05-23-2009, 01:02 AM   #1
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Registered: Apr 2009
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Slow ssh connection over lan with Ubuntu Desktop and Ubuntu Server

I have my laptop(OS Ubuntu Server 9.04) which I am planning on using for a development machine. The laptop as well as my desktop(OS Ubuntu 9.04 Desktop) are behind a D-link 655 NAT router.

I first noticed that when I ssh'ed into the laptop, the connection was quite slow. So i verbosed the ssh connection and got this. I boldered where it stalls and holds for a while

ssh -v name@
OpenSSH_5.1p1 Debian-5ubuntu1, OpenSSL 0.9.8g 19 Oct 2007
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to [] port 22.
debug1: Connection established.
debug1: identity file /home/llama/.ssh/identity type -1
debug1: identity file /home/llama/.ssh/id_rsa type -1
debug1: identity file /home/llama/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1p1 Debian-5ubuntu1
debug1: match: OpenSSH_5.1p1 Debian-5ubuntu1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.1p1 Debian-5ubuntu1
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(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: Host '' is known and matches the RSA host key.
debug1: Found key in /home/llama/.ssh/known_hosts:4
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /home/llama/.ssh/identity
debug1: Trying private key: /home/llama/.ssh/id_rsa
debug1: Trying private key: /home/llama/.ssh/id_dsa
debug1: Next authentication method: password
I then did a ping from the Desktop to the laptop and got this

ping -c4 -v
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=0.232 ms
64 bytes from icmp_seq=2 ttl=64 time=0.216 ms
64 bytes from icmp_seq=3 ttl=64 time=0.215 ms
64 bytes from icmp_seq=4 ttl=64 time=0.221 ms

--- ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3000ms
rtt min/avg/max/mdev = 0.215/0.221/0.232/0.006 ms

The ping's aren't to bad, but the initial ssh connection is very slow, how can I speed this up?

Last edited by Recursion; 05-23-2009 at 01:04 AM.
Old 05-23-2009, 02:17 AM   #2
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
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If it freezes there I'd wager that it was a DNS lookup being done on your ip at the server. Either make the DNS entry exist and within a primary DNS service being used by that server, or stop the server doing a lookup in the first place in sshd_config


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