man(1) Manual page archive

     PPP(8)                                                     PPP(8)

          ppp, pptpd - point to point protocol

          ip/ppp [ -cCdufSP ][ -b baud ][ -m mtu ][ -p dev ][ -s
          username:secret ][ -x netmntpt ][ -t modemcmd ] [ local [
          remote ] ]

          ip/pptpd [ -d ] [ -p pppnetmtpt ] [ -w window ] [ -D
          fraction ] tcp-dir

          The Point to Point Protocol is used to encapsulate Internet
          Protocol packets for transfer over serial lines or other
          protocol connections.  Ppp can run either as a client or,
          with the -S option, as a server.  The only differences
          between a client and a server is that the server will not
          believe any local address the client tries to supply it and
          that the server always initiates the authentication of the

          With no option, ppp communicates with the remote system via
          standard input and output.  This is useful if a program
          wants to use ppp in a communications stream.  However, the
          normal mode is to specify a communications device, usually a
          serial line with a modem.

          PPP supports the following options:

          p    communicate over dev instead of standard I/O

          u    before starting the PPP porotcol with the remote end,
               shuttle bytes between the device and standard I/O until
               an EOF on standard input.  This allows a user to start
               ppp and then type commands at a modem before ppp takes

          b    set the baud rate on the communications device

          f    make PPP add HDLC framing.  This is necessary when
               using PPP over a serial line or a TCP connection

          m    set the maximum transfer unit (default 1450)

          P    use this as the primary IP interface; set the default
               route through this interface and write it's configura-
               tion to /net/ndb

          s    supplies the user name and secret to be used in authen-
               ticating to the remote side.  The username is optional,

     PPP(8)                                                     PPP(8)

               the default being the local user id.  We support both
               PPP CHAP and MS CHAP

          S    run as a server

          x    use the IP stack mounted at netmntpt

          t    before starting the PPP protocol, write modemcmd to the

          c    disallow packet compression

          C    disallow ip header compression

          If both the local and remote addresses are specified, don't
          ask the other end for either or believe it if it supplies
          one.  If either is missing, get it from the remote end.

          Pptpd is the server side of a PPTP encrypted tunnel.  Tcpdir
          is the directory of a TCP connection to the client.  The TCP
          connection is used to control the tunnel while packets are
          sent back and forth using PPP inside of GRE packets.  The
          options are:

          d    write debugging output to standard error.

          p    use the IP stack mounted at pppnetmtpt to terminate the
               PPP connection.

          w    set the receive window to window.

          D    drop fraction of the received packets.  This is used
               for testing.