Linux – Login problems after changing default port ssh

debianlinuxportssh

I changed the Port in sshd_config file and restart the service (Using Linux Debian 8).
Logged out from SSH (Putty) and I tried to login later but I can't connect through Putty anymore.. I tried to login by FTP with FileZilla and that still works..

What is the problem?

Best Answer

I assume iptables are not running and blocking it. It could be SE Linux. Try running:

sestatus

If it is enabled, then run:

semanage port -l | grep ssh

And if the output says tcp 22

then run the following to add the new port (e.g. 2222)

semanage port -a -t ssh_port_t -p tcp 2222

then finally run

semanage port -l | grep ssh

which should then show 22 and 2222

and then it should work. If not then look into iptables:

iptables -nvL

will give you a list of what you have

iptables -A INPUT -p tcp --dport 2222 -j ACCEPT

would add a rule allowing traffic into port 2222, but this may not help depending on what other rules are present.

If iptables doesn't fix it then it could be a firewall between you and the server.

Related Solutions

Ssh – How to automate SSH login with password

Don't use a password. Generate a passphrase-less SSH key and push it to your VM.

If you already have an SSH key, you can skip this step… Just hit Enter for the key and both passphrases:

$ ssh-keygen -t rsa -b 2048
Generating public/private rsa key pair.
Enter file in which to save the key (/home/username/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/username/.ssh/id_rsa.
Your public key has been saved in /home/username/.ssh/id_rsa.pub.

Copy your keys to the target server:

$ ssh-copy-id id@server
id@server's password:

Now try logging into the machine, with ssh 'id@server', and check-in:

.ssh/authorized_keys

Note: If you don't have .ssh dir and authorized_keys file, you need to create it first

to make sure we haven’t added extra keys that you weren’t expecting.

Finally, check to log in…

$ ssh id@server

id@server:~$

You may also want to look into using ssh-agent if you want to try keeping your keys protected with a passphrase.

Windows – Is the password compromised because I forgot to hit Enter after ssh username

In short: yes.

# ssh 192.168.1.1 -l "myuser mypassword"
^C
# egrep "mypassword" /var/log/auth.log
Oct 19 14:33:58 host sshd[19787]: Invalid user myuser mypassword from 192.168.111.78
Oct 19 14:33:58 host sshd[19787]: Failed none for invalid user myuser mypassword from 192.168.111.78 port 53030 ssh2

Best Answer

Related Solutions

Ssh – How to automate SSH login with password

Windows – Is the password compromised because I forgot to hit Enter after ssh username

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