NAME

       parprouted - Proxy ARP IP bridging daemon

SYNOPSIS

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

DESCRIPTION

       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.

REQUIREMENTS

       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 /proc/net/arp.

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

OPTIONS

       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.

EXAMPLE

       To bridge between wlan0 and eth0: parprouted eth0 wlan0

AUTHOR

        (C) 2004, Vladimir Ivaschenko <vi@maks.net>
        http://www.hazard.maks.net