Notes on setting up bridged networking

networking-qemu-kvm-howto.txt

@@ -42,3 +42,32 @@ QEMU networking tip
 -------------------
 
 # printf 'DE:AD:BE:EF:%02X:%02X\n' $((RANDOM%256)) $((RANDOM%256))  # generates QEMU compatible mac addresses!
+
+------------------
+Bridged Networking
+------------------
+
+QEMU defaults to using NAT for its guests. It has a built-in DHCP server that
+provides addresses from the 192.168.12x.0 subnet. However, this configuration
+makes file sharing, printer sharing, and other common networking activities
+harder to use in a home network.
+
+Bridged networking allows your QEMU guest to get an address on the same subnet
+as the host computer. For example, many home networks let the wireless router
+handle IP assignment via DHCP. Here are the steps for setting up the bridge.
+
+To setup bridged networking from the command line, refer to this documentation
+at the Ubuntu website. https://help.ubuntu.com/community/KVM/Networking
+
+Ultimately, the script for booting the QEMU guest will need a line similar to
+the following to enable bridged networking in the guest:
+
+    -netdev bridge,id=net0,br=virbr0,"helper=/usr/lib/qemu/qemu-bridge-helper"
+
+On some systems the `qemu-bridge-helper` file has incorrect permissions. For it
+to work, it needs to be setuid root. This can be accomplished with this command:
+
+    $ sudo chmod u+s /usr/lib/qemu/qemu-bridge-helper
+
+Note that this is sometimes viewed as a security hole. Be careful and understand
+what you are doing before running this command.