NAME

pppd − Point-to-Point Protocol Daemon

SYNOPSIS

/usr/sbin/in.pppd [−d debug_level ] [ −w wait ]

DESCRIPTION

The in.pppd daemon manages the Point-to-Point physical connection between the local and remote PPP host.  in.pppd uses the login-password technique to establish PPP connections to remote hosts.  in.pppd uses the configuration files associated with the “Basic Network Utilities.” The method for configuring the serial IP link is similar to that used for uucp(1) or cu(1).  The serial lines may be used interchangeably for standard user logins, uucp logins, and PPP logins, and the standard uucp lock file techniques are used to share these resources. 

Upon startup, in.pppd opens a control channel to the PPP Streams kernel driver through /dev/ppcid, and then listens for:

•PPP status requests

•incoming PPP connection requests

•outgoing PPP connection requests

in.pppd listens at the port indicated in the “pppmsg” service specification (see services(4)). 

PPP status requests come from pppstat(1M), which sends requests to in.pppd through a socket.  in.pppd gets PPP status from the PPP Streams kernel driver and sends that to pppstat. 

Incoming PPP connection requests come from the PPP user shell, ppp(1M), which sends requests to pppd through a socket.  in.pppd extracts connection parameters from /etc/inet/ppphosts (see ppphosts(4)), passes the parameters to the PPP Streams kernel driver, and links the tty, through which the requester logged onto the local host, beneath the PPP Streams kernel driver. 

Outgoing PPP connection requests come from the PPP Streams kernel driver.  The PPP Streams kernel driver will send a request over the control channel to in.pppd with the desired IP address.  in.pppd searches /etc/inet/ppphosts for an entry with a host name corresponding to this IP address.  This entry, in conjunction with the /usr/lib/uucp/Systems file, is used to dial the modem (if necessary) and perform a login into the remote host.  When the remote login process completes, in.pppd links the connected tty beneath the PPP Streams kernel driver and informs PPP that the link is established. 

If password authentication is required for either incoming or outgoing connection establishment, in.pppd consults the pppauth(4) file to acquire authentication information. 

Options are:

-d debug_level
The value of debug_level specifies whether debug info is logged to the file /var/syslogd/daemon.  A value of zero logs no debug information.  A “non-zero” value logs all debug information.  The default value for debug_level is zero. 

-w wait The value of wait specifies the maximum number of PPP connection requests which the system can queue while waiting for in.pppd to execute the accept(3N) system call.  Any connection requests that arrive when the number of queued calls equals wait are discarded by the system.  The default value of wait is “5.” in.pppd passes wait as the second parameter when calling the listen(3N) system call. 

FILES

/dev/ppcid
/etc/inet/ppphosts
/etc/inet/pppauth
/usr/lib/uucp/Systems
/usr/lib/uucp/Devices

SEE ALSO

asyhdlc(7), cu(1), ppp(1M), syslogd(1M), uucp(1), ppphosts(4), ppp(7), pppstat(1M), pppauth(4)

USER CONSIDERATIONS

If an outgoing PPP connection request fails, the IP Service Provider (IPSP) will be “temporarily” marked down; however, any subsequent successful incoming connections will cause the IPSP to be marked up.