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Linux: How to block a specific IP Address using UFW


The key to blocking a specific IP address with UFW is to make sure that the rule which blocks the ipaddress is applied before any allow rules. Because the firewalls rules are run in order – the block will no come into affect if it appears at the bottom. For example on most webserver you might expect the rules to be:


To Action From
-- ------ ----
22 ALLOW Anywhere
80 ALLOW Anywhere
443 ALLOW Anywhere
22 ALLOW Anywhere (v6)
80 ALLOW Anywhere (v6)
443 ALLOW Anywhere (v6)

Therefore, to block an IP address the rules would need to setup like this:


To Action From
-- ------ ----
Anywhere DENY <ip address >
22 ALLOW Anywhere
80 ALLOW Anywhere
443 ALLOW Anywhere
22 ALLOW Anywhere (v6)
80 ALLOW Anywhere (v6)
443 ALLOW Anywhere (v6)

To do this you need to insert the new deny rule at the top using the “insert” option.

sudo ufw insert 1 deny from

To remove the block simple:

sudo ufw delete allow from

By: James