Protect your OpenSSH server on Ubuntu using UFW

To prevent abuse on your OpenSSH server, you can implement rate limiting using UFW.

To rate limit incoming SSH connections using UFW, you can use the following steps:

1) Enable UFW:

sudo ufw enable

2) Set the default policy (optional, but recommended):

sudo ufw default deny incoming

3) Rate limit SSH connections:

sudo ufw limit ssh

This will limit incoming SSH connections to 6 attempts per 30 seconds.

If you want to customize the rate limiting, you can use the following syntax:

sudo ufw limit <port> <rate> <burst>

• <port>: The port number for SSH (default is 22)
• <rate>: The number of attempts allowed per time period
• <burst>: The time period (in seconds)

Example (3 attempts per 60 seconds):

sudo ufw limit ssh 3/60

4) Reload UFW:

sudo ufw reload

This will apply the new rate limiting rules.

Note: Be careful when configuring rate limiting, as it may lock you out of your own server if you set the limits too low.

Some useful UFW commands

To check the current UFW rules:

sudo ufw status

To delete a specific rule if needed:

sudo ufw delete <rule>