====== Ubuntu - Firewall - Blocking an IP address using the route command ======

To add an IP to 127.0.0.1:

<code bash>
route add 192.16.1.100 gw 127.0.0.1 lo
</code>

----

Also it can be rejected by:

<code bash>
route add -host 192.168.1.100 reject
</code>

----

Block entire subnet 192.168.1.0/24:

<code bash>
route add -net 192.168.1.0/24 gw 127.0.0.1 lo
</code>

----

To delete this rule:

<code bash>
route del -host 192.168.1.100 reject
</code>