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32 .\" @(#)sliplogin.8 8.2 (Berkeley) 1/5/94
40 .Nd attach a serial line network interface
43 .Op Ar loginname Op Ar device
46 is used to turn the terminal line on standard input (or
50 link to a remote host. To do this, the program
52 .Pa /etc/sliphome/slip.hosts
55 (which defaults to the current login name if omitted).
56 If a matching entry is found, the line is configured appropriately
57 for slip (8-bit transparent i/o) and converted to
59 line discipline using the optional line discipline parameters.
61 The optional line discipline parameters consist of one or more of
68 which correspond respectively to
69 .Sq use normal line discipline
70 (no header compression),
71 .Sq enable VJ header compression ,
72 .Sq throw away ICMP packets ,
74 .Sq auto enable VJ header compression
75 (only if the remote end of the link also supports it).
77 Then a shell script is invoked to initialize the slip
78 interface with the appropriate local and remote
83 The usual initialization script is
84 .Pa /etc/sliphome/slip.login
85 but, if particular hosts need special initialization, the file
86 .Pa /etc/sliphome/slip.login. Ns Ar loginname
87 will be executed instead if it exists.
88 The script is invoked with the parameters
89 .Bl -tag -width slipunit
91 The unit number of the slip interface assigned to this line. E.g.,
96 The speed of the line.
98 The arguments from the
99 .Pa /etc/sliphome/slip.hosts
100 entry, in order starting with
104 Only the super-user may attach a network interface. The interface is
105 automatically detached when the other end hangs up or the
107 process dies. If the kernel slip
108 module has been configured for it, all routes through that interface will
109 also disappear at the same time. If there is other processing a site
110 would like done on hangup, the file
111 .Pa /etc/sliphome/slip.logout
113 .Pa /etc/sliphome/slip.logout. Ns Ar loginname
114 is executed if it exists. It is given the same arguments as the login script.
115 .Ss Format of /etc/sliphome/slip.hosts
116 Comments (lines starting with a `#') and blank lines (or started
117 with space) are ignored.
118 Other lines must start with a
120 but the remaining arguments can be whatever is appropriate for the
122 file that will be executed for that name.
123 Arguments are separated by white space and follow normal
125 quoting conventions (however,
128 Usually, lines have the form
129 .Bd -literal -offset indent
130 loginname local-address remote-address netmask opt-args
137 are the IP host names or addresses of the local and remote ends of the
140 is the appropriate IP netmask. These arguments are passed
144 are optional arguments used to configure the line.
145 .Sh FreeBSD Additions
146 An additional SLIP configuration file (if present) is
147 .Pa /etc/sliphome/slip.slparms .
148 If particular hosts need different configurations, the file
149 .Pa /etc/sliphome/slip.slparms. Ns Ar loginname
150 will be parsed instead if it exists.
151 .Ss Format of /etc/sliphome/slip.slparms*
152 Comments (lines starting with a `#') and blank lines (or started with
154 This file contains from one to three numeric parameters separated with spaces,
160 .Bl -tag -width keepalive
162 Set SLIP "keep alive" timeout in seconds.
163 If FRAME_END is not received in
166 closes the line and exits.
167 The default value is no timeout (zero).
169 Set SLIP "out fill" timeout in seconds.
170 It forces at least one FRAME_END
171 to be sent during this time period, which is necessary for the "keep alive"
172 timeout on the remote side.
173 The default value is no timeout (zero).
175 Set the SLIP unit number directly.
176 Use with caution, because no check is made
177 for two interfaces with same number.
178 By default sliplogin dynamically assigns the unit number.
181 If latter two parameters are omitted, they will not affect the
182 corresponding SLIP configuration.
183 If any of first two parameters is equal to zero, it will not affect
184 the corresponding SLIP configuration.
190 entry for each legal, remote slip site with
192 as the shell for that entry. E.g.,
194 Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin
197 (Our convention is to name the account used by remote host
201 Then an entry is added to
205 .Bd -literal -offset indent -compact
206 Sfoo `hostname` foo netmask
213 to the local host name and
215 is the local host IP netmask.
219 must be setuid to root and, while not a security hole, moral defectives
220 can use it to place terminal lines in an unusable state and/or deny
221 access to legitimate users of a remote slip line. To prevent this,
227 and mode 4550 so that only members of group
231 The system administrator should make sure that all legitimate users
232 are a member of the correct group.
235 logs various information to the system log daemon,
237 with a facility code of
239 The messages are listed here, grouped by severity level.
242 .Bl -tag -width Ds -compact
243 .It Sy ioctl (TCGETS): Em reason
247 to get the line parameters failed.
249 .It Sy ioctl (TCSETS): Em reason
253 to set the line parameters failed.
255 .It Sy /etc/sliphome/slip.hosts: Em reason
257 .Pa /etc/sliphome/slip.hosts
258 file could not be opened.
260 .It Sy access denied for Em user
264 .Pa /etc/sliphome/slip.hosts .
268 .Bl -tag -width Ds -compact
269 .It Sy "attaching slip unit" Em unit Sy for Ar loginname
273 was successfully attached.
276 .Bl -tag -width indent
277 .It Pa /etc/sliphome/slip.hosts
278 list of host login names and parameters.
279 .It Pa /etc/sliphome/slip.login
280 script executed when a connection is made.
281 .It Pa /etc/sliphome/slip.login. Ns Ar loginname
282 script executed when a connection is made by
284 .It Pa /etc/sliphome/slip.logout
285 script executed when a connection is lost.
286 .It Pa /etc/sliphome/slip.logout. Ns Ar loginname
287 script executed when a connection is lost by
289 .It Pa /etc/sliphome/slip.slparms
290 extra parameters file.
291 .It Pa /etc/sliphome/slip.slparms. Ns Ar loginname
292 extra parameters file for
294 .It Pa /var/run/ Ns Ar ttyXn Ns Pa .if
295 contains the name of the network interface used by the sliplogin process on
297 .It Pa /var/run/ Ns Ar slX Ns Pa .pid
298 contains the PID of the sliplogin process which is using interface
305 .Pa /usr/share/examples/sliplogin