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 loginname.
Only the superuser 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 whitespace and follow
normal sh(1)
quoting conventions (however, loginname cannot be quoted).
Usually,
lines have the form
loginname local-address remote-address netmask optargs
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 is only executable by
users in group network. To permit use, place a user into
that group.
Users in that group are of course also able to use sliplogin
to place
terminal lines in an unusable state and/or deny access to
legitimate
users of a remote slip line.
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 [Toc] [Back]
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 [Toc] [Back]
attaching slip unit unit for loginname
SLIP unit unit was successfully attached.
slattach(8), syslogd(8)
The sliplogin command is currently in beta test.
OpenBSD 3.6 August 5, 1991
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