From: Mark Wooding <mdw@distorted.org.uk>
Date: Tue, 31 May 2011 20:48:20 +0000 (+0100)
Subject: local.m4: Disable forwarding multicasts until I work out how.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/firewall/commitdiff_plain/ade2c052e531ae5d80657164affb459f5f879d5e

local.m4: Disable forwarding multicasts until I work out how.
---

diff --git a/local.m4 b/local.m4
index 05df5d6..b9fa700 100644
--- a/local.m4
+++ b/local.m4
@@ -91,6 +91,21 @@ run ip6tables -A FORWARD -j ACCEPT \
 	-m mark --mark $from_untrusted/$MASK_FROM \
 	-m state --state ESTABLISHED
 
+m4_divert(60)m4_dnl
+###--------------------------------------------------------------------------
+### Kill things we don't understand properly.
+###
+### I don't like having to do this, but since I don't know how to do proper
+### multicast filtering, I'm just going to ban it from being forwarded.
+
+errorchain poorly-understood REJECT
+
+## Ban multicast destination addresses in forwarding.
+run iptables -A FORWARD -g poorly-understood \
+	-d 224.0.0.0/4
+run ip6tables -A FORWARD -g poorly-understood \
+	-d ff::/8
+
 m4_divert(80)m4_dnl
 ###--------------------------------------------------------------------------
 ### Locally-bound packet inspection.