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NetBSD 6.1.5 - man page for sliplogin (netbsd section 8)

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

     sliplogin -- attach a serial line network interface

     sliplogin [loginname]

     sliplogin is used to turn the terminal line on standard input into a Serial Line IP (SLIP)
     link to a remote host.  To do this, the program searches the file /etc/sliphome/slip.hosts
     for an entry matching loginname (which defaults to the current login name if omitted).  If a
     matching entry is found, the line is configured appropriately for slip (8-bit transparent
     i/o) and converted to SLIP line discipline.  Then a shell script is invoked to initialize
     the slip interface with the appropriate local and remote IP address, netmask, etc.

     The usual initialization script is /etc/sliphome/slip.login but, if particular hosts need
     special initialization, the file /etc/sliphome/slip.login.loginname will be executed instead
     if it exists.  The script is invoked with the parameters

     slipunit  The unit number of the slip interface assigned to this line.  E.g., 0 for sl0.

     speed     The speed of the line.

     args      The arguments from the /etc/sliphome/slip.hosts entry, in order starting with

     Only the super-user may attach a network interface.  The interface is automatically detached
     when the other end hangs up or the sliplogin process dies.  If the kernel slip module has
     been configured for it, all routes through that interface will also disappear at the same
     time.  If there is other processing a site would like done on hangup, the file
     /etc/sliphome/slip.logout or /etc/sliphome/slip.logout.loginname is executed if it exists.
     It is given the same arguments as the login script.

   Format of /etc/sliphome/slip.hosts
     Comments (lines starting with a `#') and blank lines are ignored.	Other lines must start
     with a loginname but the remaining arguments can be whatever is appropriate for the
     slip.login file that will be executed for that name.  Arguments are separated by white space
     and follow normal sh(1) quoting conventions (however, loginname cannot be quoted).  Usually,
     lines have the form

	   loginname local-address remote-address netmask opt-args

     where local-address and remote-address are the IP host names or addresses of the local and
     remote ends of the slip line and netmask is the appropriate IP netmask.  These arguments are
     passed directly to ifconfig(8).  opt-args are optional arguments used to configure the line.

     The normal use of sliplogin is to create a /etc/passwd entry for each legal, remote slip
     site with sliplogin as the shell for that entry.  E.g.,

     Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin

     (Our convention is to name the account used by remote host hostname as Shostname.)  Then an
     entry is added to slip.hosts that looks like:

	   Sfoo    `hostname`	   foo	   netmask

     where `hostname` will be evaluated by sh(1) to the local host name and netmask is the local
     host IP netmask.

     Note that sliplogin must be setuid to root and, while not a security hole, moral defectives
     can use it to place terminal lines in an unusable state and/or deny access to legitimate
     users of a remote slip line.  To prevent this, a site can create a group, say slip, that
     only the slip login accounts are put in then make sure that /usr/sbin/sliplogin is in group
     slip and mode 4550 (setuid root, only group slip can execute binary).

     sliplogin logs various information to the system log daemon, syslogd(8), with a facility
     code of daemon.  The messages are listed here, grouped by severity level.

     Error Severity
     ioctl (TCGETS): reason
	     A TCGETS ioctl() to get the line parameters failed.

     ioctl (TCSETS): reason
	     A TCSETS ioctl() to set the line parameters failed.

     /etc/sliphome/slip.hosts: reason
	     The /etc/sliphome/slip.hosts file could not be opened.

     access denied for user
	     No entry for user was found in /etc/sliphome/slip.hosts.

     Notice Severity
     attaching slip unit unit for loginname
	     SLIP unit unit was successfully attached.

     sl(4), slattach(8), syslogd(8)

     The sliplogin command is currently in beta test.

BSD					 January 5, 1994				      BSD
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