PPPOE-RELAY(8)PPPOE-RELAY(8)NAMEpppoe-relay - user-space PPPoE relay agent.
SYNOPSISpppoe-relay [options]
DESCRIPTIONpppoe-relay is a user-space relay agent for PPPoE (Point-to-Point Pro‐
tocol 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 termi‐
nated. 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 fre‐
quently 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 back‐
ground; instead, it remains in the foreground.
-h The -h option prints a brief usage message and exits.
OPERATIONpppoe-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 inter‐
faces 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 con‐
centrator.
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 dupli‐
cate 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 ses‐
sions. 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 ses‐
sion 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 INVOCATIONSpppoe-relay-C eth0 -S eth1
The example above relays frames between PPPoE clients on the eth0 net‐
work 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.
AUTHORSpppoe-relay was written by David F. Skoll <dfs@roaringpenguin.com>.
The pppoe home page is http://www.roaringpenguin.com/pppoe/.
SEE ALSOpppoe-start(8), pppoe-stop(8), pppoe-connect(8), pppd(8),
pppoe.conf(5), pppoe(8), pppoe-setup(8), pppoe-status(8), pppoe-
sniff(8), pppoe-server(8)4th Berkeley Distribution 26 January 2001 PPPOE-RELAY(8)