I have an Ubuntu 12.04 laptop that is taking so long to connect to various servers (in different data centres) that it seems like a bit of a lottery whether I'll actually get a connection. If I connect to the servers between themselves it's instantaneous, and I've set
UseDNS no AddressFamily inet
On the servers I'm connecting to (and rebooted for good measure). I also put in the reverse DNS+IP of the cable connection I'm connecting from. If I connect from the laptop via telnet:
telnet my.server 22
Then the connection is also instantaneous, so it doesn't appear to be a problem with an intervening firewall. I have the same behaviour whether I connect with the IP, a short name in my hosts or the FQDN. I'm connecting with a 50mbps (cable, sync) connection so that doesn't appear to be the problem, and when I do finally get a connection then it's a good, quick, stable one. I have tried listening on another port (8000) and that makes no difference. Web and other connections from the laptop to the machine are also very good.
If I increase logging then I get the following before it hangs:
$ ssh -vvv flip OpenSSH_5.9p1 Debian-5ubuntu1.1, OpenSSL 1.0.1 14 Mar 2012 debug1: Reading configuration data /home/anton/.ssh/config debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to flip [xxx.xxx.xxx.xxx] port 22. debug1: Connection established. debug3: Incorrect RSA1 identifier debug3: Could not load "/home/anton/.ssh/id_rsa" as a RSA1 public key debug1: identity file /home/anton/.ssh/id_rsa type 1 debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048 debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048 debug1: identity file /home/anton/.ssh/id_rsa-cert type -1 debug1: identity file /home/anton/.ssh/id_dsa type -1 debug1: identity file /home/anton/.ssh/id_dsa-cert type -1 debug1: identity file /home/anton/.ssh/id_ecdsa type -1 debug1: identity file /home/anton/.ssh/id_ecdsa-cert type -1
It's hanging on the server between the following two lines:
Nov 6 13:51:57 srv sshd: Connection from XXX.XXX.XXX.XXX port 51099 Nov 6 13:53:03 srv sshd: debug1: Client protocol version 2.0; client software version OpenSSH_5.9p1 Debian-5ubuntu1.1
It's a least quicker than yesterday though!
Does anyone have any ideas here?