/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
/etc/sliphome/slip.hosts
entry, in order starting with
loginname.
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.
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.
/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).
Error Severity
TCGETS
ioctl(
)
to get the line parameters failed.
TCSETS
ioctl(
)
to set the line parameters failed.
/etc/sliphome/slip.hosts
file could not be opened.
/etc/sliphome/slip.hosts
.
Notice Severity