IP Tables Junkfilter Agent¶
This agent will add, query and remove iptables rules to a specific iptables chain called junk_filter.
I use a specific table here since I have a list of all my bad IPs that I can just jump to whenever I want to block this traffic.
-I INPUT -p tcp --dport 22 -j junk_filter -I INPUT -p tcp --dport 22 --syn -j ACCEPT
Something like this will block all the junk filtered ips but just allow. My IDS use this rule to block people who do SSH brute force scans and so forth against my servers, I get to pick which ports are subject to this filter using the rule patten above.
At present you can only block specific single IP Addresses
- Each node need to first have the junk_filter rule on it, the agent wont create an empty one
- The source is on GitHub
- Follow the basic plugin install guide
Keep in mind:
- You need to thoroughly test this code outside of production, make very certain it does what you expect.
- MCollective will need to run as root for this to work
- Did I mention you need to test it works?
By default the agent will use the DROP target, you can configure it in server.cfg:
plugin.iptables.target = REJECT
You can block an IP:
% mc-iptables block 192.168.1.1 * [ ============================================================> ] 17 / 17 Finished processing 17 / 17 hosts in 523.23 ms
Query the IP:
% mc-iptables -I some.node isblocked 192.168.1.1 * [ ============================================================> ] 1 / 1 some.node 192.168.1.1 is blocked Finished processing 1 / 1 hosts in 536.96 ms
Unblock the IP:
% mc-iptables unblock 192.168.1.1 * [ ============================================================> ] 17 / 17 Finished processing 17 / 17 hosts in 520.98 ms
The agent is a SimpleRPC agent, you can interact with it via the normal RPC methods:
% mc-rpc iptables isblocked ipaddr=192.168.1.1 -I some.node Determining the amount of hosts matching filter for 2 seconds .... 17 * [ ============================================================> ] 1 / 1 some.node Result: 192.168.1.1 is not blocked Finished processing 1 / 1 hosts in 523.30 ms