pppoe-relay(8) -- Linux man page
NAME
pppoe-relay - user-space PPPoE relay agent.
SYNOPSIS
pppoe-relay [options]
DESCRIPTION
pppoe-relay is a user-space relay agent for PPPoE
(Point-to-Point Protocol over Ethernet) for Linux. pppoe-relay
works in concert with the pppoe client and pppoe-server
server. See the OPERATION section later in this manual for
details on how pppoe-relay works.
OPTIONS
- -S interface
-
Adds the Ethernet interface interface to the list of interfaces
managed by pppoe-relay. Only PPPoE servers may be connected to
this interface.
- -C interface
-
Adds the Ethernet interface interface to the list of interfaces
managed by pppoe-relay. Only PPPoE clients may be connected to
this interface.
- -B interface
-
Adds the Ethernet interface interface to the list of interfaces
managed by pppoe-relay. Both PPPoE clients and servers may be
connected to this interface.
- -n num
-
Allows at most num concurrent PPPoE sessions. If not specified,
the default is 5000. num can range from 1 to 65534.
- -i timeout
-
Specifies the session idle timeout. If both peers in a session are idle
for more than timeout seconds, the session is terminated.
If timeout is specified as zero, sessions will never be terminated
because of idleness.
Note that the idle-session expiry routine is never run more frequently than
every 30 seconds, so the timeout is approximate. The default value for
timeout is 600 seconds (10 minutes.)
- -F
-
The -F option causes pppoe-relay not to fork into the
background; instead, it remains in the foreground.
- -h
-
The -h option prints a brief usage message and exits.
OPERATION
pppoe-relay listens for incoming PPPoE PADI frames on all interfaces
specified with -B or -C options. When a PADI frame appears,
pppoe-relay adds a Relay-Session-ID tag and broadcasts the PADI
on all interfaces specified with -B or -S options (except the
interface on which the frame arrived.)
Any PADO frames received are relayed back to the client which sent the
PADI (assuming they contain valid Relay-Session-ID tags.) Likewise,
PADR frames from clients are relayed back to the matching access
concentrator.
When a PADS frame is received, pppoe-relay enters the two peers'
MAC addresses and session-ID's into a hash table. (The session-ID seen
by the access concentrator may be different from that seen by the client;
pppoe-relay must renumber sessions to avoid the possibility of duplicate
session-ID's.) Whenever either peer sends a session frame, pppoe-relay
looks up the session entry in the hash table and relays the frame to
the correct peer.
When a PADT frame is received, pppoe-relay relays it to the peer
and deletes the session entry from its hash table.
If a client and server crash (or frames are lost), PADT frames may never
be sent, and pppoe-relay's hash table can fill up with stale sessions.
Therefore, a session-cleaning routine runs periodically, and removes old
sessions from the hash table. A session is considered "old" if no traffic
has been seen within timeout seconds. When a session is deleted because
of a timeout, a PADT frame is sent to each peer to make certain that they
are aware the session has been killed.
EXAMPLE INVOCATIONS
pppoe-relay -C eth0 -S eth1
The example above relays frames between PPPoE clients on the eth0 network
and PPPoE servers on the eth1 network.
pppoe-relay -B eth0 -B eth1
This example is a transparent relay -- frames are relayed between any mix
of clients and servers on the eth0 and eth1 networks.
pppoe-relay -S eth0 -C eth1 -C eth2 -C eth3
This example relays frames between servers on the eth0 network and
clients on the eth1, eth2 and eth3 networks.
AUTHORS
pppoe-relay was written by David F. Skoll <dfs@roaringpenguin.com>.
The pppoe home page is http://www.roaringpenguin.com/pppoe/.
SEE ALSO
adsl-start(8), adsl-stop(8), adsl-connect(8), pppd(8), pppoe.conf(5),
pppoe(8), adsl-setup(8), adsl-status(8), pppoe-sniff(8), pppoe-server(8)
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