Tips to change ssh connection port number in ubuntu

Generally

Open ssh configuration file

sudo vim /etc/ssh/sshd_config

Find the following line:

Port 22

Change the following 22 to the port number you want to set

Then restart the ssh service

sudo service ssh restart

If you are prompted with the message: no route to host when logging in to SSH remotely, it may be that the firewall has not configured the corresponding port. Set the firewall and it will be ok.

If you have not installed openssh-server, please refer to the following steps

Note: If the port is modified remotely, in order to prevent SSH from being unable to connect remotely after modifying the port, we can make SSH work under 22 and the newly set port at the same time, and then comment out the 22 port after the test can connect to the new port. Lose.

First install openssh-server

$ sudo apt-get install openssh-server

$sudo vim /etc/ssh/sshd_config

Remove the # in front of #Port 22 and add the port you want to use on the next line. For example: Port 222

$ sudo vim /etc/ssh/ssh_config

Remove the # in front of #Port 22 and add the port you want to use on the next line. For example: Port 222

Restart the service after saving the changes

$ /etc/init.d/ssh restart

or

$ service ssh restart

Open the corresponding port in the firewall and conduct the test (note that ssh now works under 22 and the port you set at the same time. After the test is completed, you can comment out Port 22)

Ubuntu 16.04 Modify ssh port

Modify/etc/ssh/sshd_config

$sudo vim /etc/ssh/sshd_config

Add your port under Port 22

Port 22
Port YOUR_PORT

Modify /etc/ssh/ssh_config and add your port under Host *

Host *
Port 22
Port your port
#ForwardAgent no
...

Restart ssh

service ssh restart

Then ssh to connect to the new port. After successful connection, modify the above configuration and comment out port 22

Create a new config file under ~/.ssh/ on this machine. The content of the file is:

Host YOUR_HOST
User YOUR_USER_NAME
Port YOUR_NEW_PORT

In this way, you only need to ssh YOUR_HOST to connect next time and it will be ok.

After modifying the ssh default port, some remote operations of git will fail. The solution is to modify the config file:

Host github.com
HostName github.com
Port 22
Host bitbucket.org
HostName bitbucket.org
Port 22

There is another faster method:

1. Set port

sed -i "s/Port .*/Port your port/g" /etc/ssh/sshd_config

2. Restart ssh

service ssh restart

Then ssh to connect to the new port.

Notice:

The new port should be added to the list of allowed access, so as not to lock yourself out of the server! ! ! Refer here, the command entered on the Linux command line is:

firewall-cmd --zone=public --add-port=your port/tcp --permanent

Check Auth.log and check whether SSH has been scanned
Check the IP addresses and times of successful login with password

grep "Accepted password for root" /var/log/auth.log | awk '{print $11}' | sort | uniq -c | sort -nr | more

Check the IP address and number of failed login attempts with password

grep "Failed password for root" /var/log/auth.log | awk '{print $11}' | sort | uniq -c | sort -nr | more

The above is the detailed content of Tips to change ssh connection port number in ubuntu. For more information, please follow other related articles on the PHP Chinese website!