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       parprouted - Proxy ARP IP bridging daemon


       parprouted [-d] [-p] interface [interface]


       parprouted is a daemon for transparent IP (Layer 3) proxy ARP bridging.
       Unlike standard bridging, proxy ARP bridging allows to bridge Ethernet
       networks behind wireless nodes. Normal L2 bridging does not work
       between wireless nodes because wireless does not know about MAC
       addresses used in the wired Ethernet networks. Also this daemon is
       useful for making transparent firewalls.

       The daemon listens for incoming ARP requests, and in case the location
       of the requested IP address is unknown, forwards them to other
       interfaces, as well as updates kernel ARP table with the received
       replies. When necessary, the daemon generates an ARP reply itself,
       which causes the stations to send traffic to the host daemon is running
       on. By automatically adding appropriate /32 routes to Linux kernel IP
       routing table for the hosts learned via ARP, daemon ensures that the
       Linux kernel will be able to route the packets to the destination host
       when it receives them without any need routing/subnetting manually.

       All routes entered by the daemon have a metric of 50.

       Unless you use -p switch, all entries in the ARP table will be
       refreshed (rechecked by sending ARP requests) every 50 seconds. This
       keeps them from being expired by kernel.

       Normally it takes about 60 ms for a bridge to update all its tables and
       start sending packets to the destination.


       This daemon can be used for unicast traffic only. I.e., DHCP is not
       supported.  Use software such as dhcrelay to "bridge" DHCP.

       You should have an IP address assigned on all of your interfaces that
       you do bridging on. There is no need for this address to be from the
       same networks as the bridged networks. Any dummy address will do.

       The system should have correct default route.

       parprouted requires "ip" program from iproute2 tools to be installed in
       /sbin. If it is installed in another location, please replace
       "/sbin/ip" occurances in the source with the correct path. As well you
       should have proc filesystem mounted in /proc because the daemon uses

       parprouted is designed for and tested only with Linux 2.4.x kernels.


       The list of interfaces to do bridging on should be given via the
       command line.

       The daemon accepts the following switches:

       -d, which stands for debugging. If you run it in debugging mode the
       daemon will not go to background and will print additional debugging
       information to stdout/stderr.

       -p, which makes all ARP entries to be permanent. This will also result
       in that ARP tables will not be refreshed by ARP pings.


       To bridge between wlan0 and eth0: parprouted eth0 wlan0


        (C) 2004, Vladimir Ivaschenko <>