X-Git-Url: https://git.distorted.org.uk/~mdw/firewall/blobdiff_plain/c8d422ecbe80759b2a92214920ade76592e02153..6d47692a3e4e8e1da37a09019b5c8361e0004bd4:/bookends.m4

diff --git a/bookends.m4 b/bookends.m4
index 495e95a..02f7859 100644
--- a/bookends.m4
+++ b/bookends.m4
@@ -58,9 +58,14 @@ setopt icmp_echo_ignore_broadcasts 0
 ## Turn off iptables filtering for bridges.  We'll use ebtables if we need
 ## to; but right now the model is that we do filtering at the borders, and
 ## are tolerant of things which are local.
-for filter in arptables iptables ip6tables; do
-  run sysctl -q net/bridge/bridge-nf-call-$filter=0
-done
+if [ -x /sbin/brctl ]; then
+  modprobe bridge || :
+  if [ -d /proc/sys/net/bridge ]; then
+    for filter in arptables iptables ip6tables; do
+      run sysctl -q net.bridge.bridge-nf-call-$filter=0
+    done
+  fi
+fi
 
 ## Turn on the reverse-path filter, and log weird things.
 setdevopt rp_filter 1