X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=INSTALL.userspace;h=10511b1653912bd1539c9db40c9433f04dd7e7e2;hb=refs%2Fheads%2Fof1.1;hp=6e6fcd49a78ab2d6d11af7635e54d39decb38c0f;hpb=045b2e5c77d02cd0d7bba046e2dbed72ec4828c8;p=openvswitch

diff --git a/INSTALL.userspace b/INSTALL.userspace
index 6e6fcd49..10511b16 100644
--- a/INSTALL.userspace
+++ b/INSTALL.userspace
@@ -47,6 +47,19 @@ ovs-vswitchd will create a TAP device as the bridge's local interface,
 named the same as the bridge, as well as for each configured internal
 interface.
 
+Firewall Rules
+--------------
+
+On Linux, when a physical interface is in use by the userspace
+datapath, packets received on the interface still also pass into the
+kernel TCP/IP stack.  This can cause surprising and incorrect
+behavior.  You can use "iptables" to avoid this behavior, by using it
+to drop received packets.  For example, to drop packets received on
+eth0:
+
+    iptables -A INPUT -i eth0 -j DROP
+    iptables -A FORWARD -i eth0 -j DROP
+
 Bug Reporting
 -------------