MirBSD manpage: pppoe(8)

PPPOE(8)                 BSD System Manager's Manual                  PPPOE(8)


     pppoe - PPP Over Ethernet translator


     pppoe [-stv] [-i interface] [-n service] [-p system]


     The pppoe program can, with the help of ppp(8), act as a server or client
     for running PPP Over Ethernet.

     The options are as follows:

     -i interface
             Specify the interface that pppoe is to use, which should be a
             real Ethernet interface (not a virtual device like tun(4)). If
             this option is not specified, pppoe will use the first Ethernet
             interface that is up and running.

     -n service
             Use service as the service name when negotiating with the server.
             By default, the client will ask for any service, and expect the
             server to respond with the same.

     -p system
             This argument is passed, uninterpreted, to ppp(8). It can be used
             to specify the configuration data to be used for PPP Over Ether-
             net connections. This option is only used in server mode.

     -s      If this option is specified, pppoe will run as a server. Other-
             wise, pppoe runs as a client.

     -t      Instruct pppoe to ignore PADT packets.  If you observe numerous
             "connection reset by peer" error messages and constantly lose
             connection soon after establishing one, it may because of spuri-
             ous PADT tags being sent from the peer.  Ignoring them may al-
             leviate the problem.

     -v      For each use of the flag, the verbosity of pppoe increases.


     Configuring the client involves setting up the configuration file for
     ppp(8). The following statements must be included in the file for the
     specified system (or ``default'' if no system is specified):

           set device "!/usr/sbin/pppoe"
           set mtu max 1446
           set mru max 1446
           set speed sync
           disable acfcomp protocomp
           deny acfcomp

     The set device line tells ppp to use pppoe program for input and output
     instead of using a serial port or other network connection. The mtu and
     mru must be set to at maximum 1492, better 1446 (see below), to leave
     room in the outgoing Ethernet packet for the pppoe headers. The set speed
     sync line tells ppp to use synchronous encoding for the packets sent
     between it and pppoe. According to RFC 2516, protocol compression,
     protocomp, is not recommended, so it is disabled, but not denied. On the
     other hand, address and control field compression, acfcomp, must be dis-
     abled and denied.

     Additionally, the authentication mechanism for the connection must be
     specified as well as any other parameters.


     Given a machine with one Ethernet interface, xl0, the first thing that
     must be done is to bring the interface up:

           # ifconfig xl0 up

     This can be done automatically during boot with a /etc/hostname.xl0 file,
     see hostname.if(5) for details.

     Next, a /etc/ppp/ppp.conf file must be created. Below is a minimal PPPoE
     style configuration, see ppp(8) for more options.

              set log Phase Chat LCP IPCP CCP tun command

              set device "!/usr/sbin/pppoe -i xl0"
              set mtu max 1446
              set mru max 1446
              set speed sync
              disable acfcomp protocomp
              deny acfcomp
              set authname "myUsername"
              set authkey "myPassword"

     The default section sets up some helpful information to log while getting
     started, and the pppoe section sets the required fields for a PPPoE con-
     nection as well as the username and password to use to authenticate to
     the service provider.

     Once the /etc/ppp/ppp.conf file is set up, it is just a matter of setting
     ppp(8) into action:

           # ppp pppoe
           Working in interactive mode
           Using interface: tun0
           ppp ON deepthought> dial
           Ppp ON deepthought>
           PPp ON deepthought>
           PPP ON deepthought>

     The userland ppp(8) daemon has many options for configuration, like ad-
     ding default routes, network address translation, automatically using re-
     mote DNS servers, automatic dialing, etc. Please see ppp(8) for details.

     Several ppp(8) options are particularly helpful when used with pppoe.

     enable lqr / accept lqr
             Enable and accept link quality requests, which can be used to
             detect whether the link has gone down.

     enable mssfixup
             Allow ppp(8) to adjust the maximum segment size on outgoing SYN


     tun(4), hostname.if(5), ifconfig(8), ppp(8), pppoe(4)

     L. Mamakos, et al., RFC 2516 A Method for Transmitting PPP Over Ethernet.

     For an explanation how PPPoE is further encapsulated on the way to your
     ISP, and why 1446 is the optimum MTU for native IPv4 and native IPv6
     connections, go to (changing User-Agent to foo in lynx)
     http://whirlpool.net.au/wiki/adsl_theory_ppp. Tunneled IPv6 connections
     using gif(4) tunnels have an optimum MTU of 1426, the difference is just
     the size of an IPv4 header for the simple encapsulation; the maximum TCP-
     MSS would be 1406 and 1386, respectively.


     This implementation of pppoe first appeared in OpenBSD 2.8.


     The pppoe program was written by Jason L. Wright <jason@thought.net> of
     Network Security Technologies, Inc. <http://www.netsec.net>.


     This software runs completely in user mode. As such it will have much
     more overhead than pppoe(4), a kernel implementation.

     The service is not currently used by the server code.

MirBSD #10-current              June 16, 2016                                2

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