Describe dummy test model. Work on OpenFlow intro.

[openvswitch] / INSTALL.userspace

diff --git a/INSTALL.userspace b/INSTALL.userspace
index 6e6fcd49a78ab2d6d11af7635e54d39decb38c0f..296f0771c6f4cf3adaa3ab5d5fc35951c5788a61 100644 (file)
--- a/INSTALL.userspace
+++ b/INSTALL.userspace
@@ -17,7 +17,7 @@ Building and Installing
 -----------------------
 
 The requirements and procedure for building, installing, and
-configuring Open vSwitch are the same as those given in INSTALL.Linux.
+configuring Open vSwitch are the same as those given in INSTALL.
 You may omit configuring, building, and installing the kernel module,
 and the related requirements.
 
@@ -31,6 +31,10 @@ The tun device must also exist as /dev/net/tun.  If it does not exist,
 then create /dev/net (if necessary) with "mkdir /dev/net", then create
 /dev/net/tun with "mknod /dev/net/tun c 10 200".
 
+On FreeBSD, the userspace switch additionally requires the kernel
+tap(4) driver to be available, either built into the kernel or loaded
+as a module.
+
 Using the Userspace Datapath with ovs-vswitchd
 ----------------------------------------------
 
@@ -47,6 +51,19 @@ 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
 -------------