pppoe-relay(8)

1PPPOE-RELAY(8)              System Manager's Manual             PPPOE-RELAY(8)
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NAME

6       pppoe-relay - user-space PPPoE relay agent.
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SYNOPSIS

9       pppoe-relay [options]
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DESCRIPTION

13       pppoe-relay  is a user-space relay agent for PPPoE (Point-to-Point Pro‐
14       tocol over Ethernet) for Linux.  pppoe-relay works in concert with  the
15       pppoe  client and pppoe-server server.  See the OPERATION section later
16       in this manual for details on how pppoe-relay works.
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OPTIONS

20       -S interface
21              Adds the Ethernet interface interface to the list of  interfaces
22              managed  by pppoe-relay.  Only PPPoE servers may be connected to
23              this interface.
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26       -C interface
27              Adds the Ethernet interface interface to the list of  interfaces
28              managed  by pppoe-relay.  Only PPPoE clients may be connected to
29              this interface.
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32       -B interface
33              Adds the Ethernet interface interface to the list of  interfaces
34              managed  by  pppoe-relay.  Both PPPoE clients and servers may be
35              connected to this interface.
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38       -n num Allows at most num concurrent PPPoE sessions.  If not specified,
39              the default is 5000.  num can range from 1 to 65534.
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42       -i timeout
43              Specifies  the session idle timeout.  If both peers in a session
44              are idle for more than timeout seconds, the  session  is  termi‐
45              nated.   If timeout is specified as zero, sessions will never be
46              terminated because of idleness.
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48              Note that the idle-session expiry routine is never run more fre‐
49              quently  than  every  30 seconds, so the timeout is approximate.
50              The default value for timeout is 600 seconds (10 minutes.)
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53       -F     The -F option causes pppoe-relay not  to  fork  into  the  back‐
54              ground; instead, it remains in the foreground.
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57       -h     The -h option prints a brief usage message and exits.
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OPERATION

61       pppoe-relay  listens  for  incoming PPPoE PADI frames on all interfaces
62       specified with -B or -C options.  When a PADI frame appears,  pppoe-re‐
63       lay  adds  a Relay-Session-ID tag and broadcasts the PADI on all inter‐
64       faces specified with -B or -S options (except the  interface  on  which
65       the frame arrived.)
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67       Any  PADO frames received are relayed back to the client which sent the
68       PADI (assuming they contain valid  Relay-Session-ID  tags.)   Likewise,
69       PADR  frames  from clients are relayed back to the matching access con‐
70       centrator.
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72       When a PADS frame is received, pppoe-relay enters the  two  peers'  MAC
73       addresses  and session-ID's into a hash table.  (The session-ID seen by
74       the access concentrator may be different from that seen by the  client;
75       pppoe-relay  must  renumber sessions to avoid the possibility of dupli‐
76       cate session-ID's.)  Whenever either peer sends a session frame, pppoe-
77       relay looks up the session entry in the hash table and relays the frame
78       to the correct peer.
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80       When a PADT frame is received, pppoe-relay relays it to  the  peer  and
81       deletes the session entry from its hash table.
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83       If  a  client  and  server  crash (or frames are lost), PADT frames may
84       never be sent, and pppoe-relay's hash table can fill up with stale ses‐
85       sions.   Therefore,  a  session-cleaning routine runs periodically, and
86       removes old sessions from the hash  table.   A  session  is  considered
87       "old"  if no traffic has been seen within timeout seconds.  When a ses‐
88       sion is deleted because of a timeout, a PADT frame is sent to each peer
89       to make certain that they are aware the session has been killed.
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EXAMPLE INVOCATIONS

93       pppoe-relay -C eth0 -S eth1
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95       The  example above relays frames between PPPoE clients on the eth0 net‐
96       work and PPPoE servers on the eth1 network.
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98       pppoe-relay -B eth0 -B eth1
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100       This example is a transparent relay -- frames are relayed  between  any
101       mix of clients and servers on the eth0 and eth1 networks.
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103       pppoe-relay -S eth0 -C eth1 -C eth2 -C eth3
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105       This  example  relays  frames  between  servers on the eth0 network and
106       clients on the eth1, eth2 and eth3 networks.
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AUTHORS

110       pppoe-relay was written by Dianne Skoll <dianne@skoll.ca>.
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112       The pppoe home page is https://dianne.skoll.ca/projects/rp-pppoe/.
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