Cannot establish ssh connection to computer on local network

Question

I've just (re)installed ubuntu 11.10 on my main pc, and the connection times out every time I try to ssh connect to my laptop (over the local network) to retrieve the files I backed up there. The connection times out every time I try to connect.

I can establish a connection in the other direction without issue.

Here's the verbose output I get when I try to connect:

ovangle@ruby-EP43-DS3:~$ ssh -v [email protected]
OpenSSH_5.8p1 Debian-7ubuntu1, OpenSSL 1.0.0e 6 Sep 2011
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 10.1.1.4 [10.1.1.4] port 22.
debug1: connect to address 10.1.1.4 port 22: Connection timed out
ssh: connect to host 10.1.1.4 port 22: Connection timed out

ssh is installed on both machines, and I've tried deleting '~/.ssh/known_hosts' on both machines, still nada.

I've changed the sshd logging on the laptop to VERBOSE and restarted the daemon (because I wasn't getting any relevant syslog entries otherwise), and this is the log for the most recent connection attempt.

EDIT: posted wrong logs last time. They just showed that there was a connection received, they weren't actually the sshd logs (which were in auth.log as I recently discovered). Unfortunately, that log is filling up with extremely weird error messages and it gives me no information about the connection.

Nov  8 16:02:18 ovangle-A6Rp pkexec: pam_unix(polkit-1:session): session opened for user root by (uid=1000)
Nov  8 16:02:18 ovangle-A6Rp pkexec: pam_ck_connector(polkit-1:session): cannot determine display-device
Nov  8 16:02:18 ovangle-A6Rp pkexec[6270]: ovangle: Executing command [USER=root] [TTY=unknown] [CWD=/home/ovangle] [COMMAND=/usr/sbin/gnome-power-backlight-helper --set-brightness 2]
Nov  8 16:02:19 ovangle-A6Rp pkexec: pam_unix(polkit-1:session): session opened for user root by (uid=1000)
Nov  8 16:02:19 ovangle-A6Rp pkexec: pam_ck_connector(polkit-1:session): cannot determine display-device
Nov  8 16:02:19 ovangle-A6Rp pkexec[6273]: ovangle: Executing command [USER=root] [TTY=unknown] [CWD=/home/ovangle] [COMMAND=/usr/sbin/gnome-power-backlight-helper --set-brightness 7]

Solution 1

Make sure you install the openssh server in the main PC (where you are trying to ssh into)

sudo apt-get install openssh-server

then check if the Ubuntu firewall is turne on?

sudo ufw status

if yes or no still issue the following command

sudo ufw allow ssh and sudo ufw reload

Now try to ssh using

ssh user@ip-address-of-the-machine

If this doesn't work try to add the INPUT and OUTPUT firewall rule in IPTABLE

sudo iptables -I INPUT -p tcp --dport 22 -j ACCEPT

sudo iptables -I OUTPUT -p tcp --dport 22 -j ACCEPT

sudo iptables-save

sudo service iptables restart

You might have to restart the network manager as well. Good Luck!

Solution 2

Ensure you have the ssh server running by running the below on the machine you wish to connect to:

service ssh status

If that returns start/running, process pid then it is running ok. If not run

service ssh start

and check the output that it starts correctly. If it is started correctly and you still can not ssh to the machine then on the remote host install nmap

apt-get install nmap

Nmap (Network Mapper) is a port scanner which is useful for this kind of stuff. Run the below on the computer you are connecting from

nmap *ipaddress/hostname of computer you are trying to connect to*

and check the 22/tcp or ssh is shown as open.

refer to Ubuntu iptables to learn how to open the ports.

Comments

[Admin]

Try to use verbose, eg. "ssh -vvv username@laptop" and post the relevant output.

[Admin]

Do you have openssh-server installed on both machines?

[Admin]

updated the post with the relevant output. Also, both machines have openssh-server installed.

[Admin]

What does sshd log on the laptop when connecting to there?

[Admin]

on the machine you're trying to connect to do a sudo service ssh restart and see what the output is.

[Admin]

The same happens to me, it seems that when you logoff, Network Manager closes and then you are not only unable to conect using ssh, but even to do a single ping. I am currently looking for a solution but what you can do is to just block the screen and do not logoff. This may work.

[Admin]

Don't you have iptables rules on your laptop that would prevent SSH ? Do iptables -L to list the rules if they are activated. If you have firewall rules activated, you must have at least one allowing traffic (ACCEPT) to TCP port 22.