iptables cheat sheet

howto/incident-response.md

@@ -86,6 +86,13 @@ Open a ticket by writing <support@cymru.com>.
 
 TBD
 
+## Network-level attacks
+
+If you are *sure* that a specific `$IP` is mounting a Denial of Service
+attack on a server, you can block it with:
+
+    iptables -A INPUT -s $IP -j DROP
+
 # Support policies
 
 Please see [/policy/tpa-rfc-2-support/](https://gitlab.torproject.org/anarcat/wikitest/-/wikis/policy/tpa-rfc-2-support/)