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32 .\" @(#)sliplogin.8 8.2 (Berkeley) 1/5/94
33 .\" $FreeBSD: src/usr.sbin/sliplogin/sliplogin.8,v 1.12.2.5 2003/03/11 22:31:33 trhodes Exp $
34 .\" $DragonFly: src/usr.sbin/sliplogin/sliplogin.8,v 1.2 2003/06/17 04:30:03 dillon Exp $
41 .Nd attach a serial line network interface
44 .Op Ar loginname Op Ar device
48 utility is used to turn the terminal line on standard input (or
52 link to a remote host. To do this, the program
54 .Pa /etc/sliphome/slip.hosts
57 (which defaults to the current login name if omitted).
58 If a matching entry is found, the line is configured appropriately
59 for slip (8-bit transparent i/o) and converted to
61 line discipline using the optional line discipline parameters.
63 The optional line discipline parameters consist of one or more of
70 which correspond respectively to
71 .Sq use normal line discipline
72 (no header compression),
73 .Sq enable VJ header compression ,
74 .Sq throw away ICMP packets ,
76 .Sq auto enable VJ header compression
77 (only if the remote end of the link also supports it).
79 Then a shell script is invoked to initialize the slip
80 interface with the appropriate local and remote
85 The usual initialization script is
86 .Pa /etc/sliphome/slip.login
87 but, if particular hosts need special initialization, the file
88 .Pa /etc/sliphome/slip.login. Ns Ar loginname
89 will be executed instead if it exists.
90 The script is invoked with the parameters
91 .Bl -tag -width slipunit
93 The unit number of the slip interface assigned to this line. E.g.,
98 The speed of the line.
100 The arguments from the
101 .Pa /etc/sliphome/slip.hosts
102 entry, in order starting with
106 Only the super-user may attach a network interface. The interface is
107 automatically detached when the other end hangs up or the
109 process dies. If the kernel slip
110 module has been configured for it, all routes through that interface will
111 also disappear at the same time. If there is other processing a site
112 would like done on hangup, the file
113 .Pa /etc/sliphome/slip.logout
115 .Pa /etc/sliphome/slip.logout. Ns Ar loginname
116 is executed if it exists. It is given the same arguments as the login script.
117 .Ss Format of /etc/sliphome/slip.hosts
118 Comments (lines starting with a `#') and blank lines (or started
119 with space) are ignored.
120 Other lines must start with a
122 but the remaining arguments can be whatever is appropriate for the
124 file that will be executed for that name.
125 Arguments are separated by white space and follow normal
127 quoting conventions (however,
130 Usually, lines have the form
131 .Bd -literal -offset indent
132 loginname local-address remote-address netmask opt-args
139 are the IP host names or addresses of the local and remote ends of the
142 is the appropriate IP netmask. These arguments are passed
146 are optional arguments used to configure the line.
147 .Sh FreeBSD Additions
148 An additional SLIP configuration file (if present) is
149 .Pa /etc/sliphome/slip.slparms .
150 If particular hosts need different configurations, the file
151 .Pa /etc/sliphome/slip.slparms. Ns Ar loginname
152 will be parsed instead if it exists.
153 .Ss Format of /etc/sliphome/slip.slparms*
154 Comments (lines starting with a `#') and blank lines (or started with
156 This file contains from one to three numeric parameters separated with spaces,
162 .Bl -tag -width keepalive
164 Set SLIP "keep alive" timeout in seconds.
165 If FRAME_END is not received in
168 closes the line and exits.
169 The default value is no timeout (zero).
171 Set SLIP "out fill" timeout in seconds.
172 It forces at least one FRAME_END
173 to be sent during this time period, which is necessary for the "keep alive"
174 timeout on the remote side.
175 The default value is no timeout (zero).
177 Set the SLIP unit number directly.
178 Use with caution, because no check is made
179 for two interfaces with same number.
180 By default sliplogin dynamically assigns the unit number.
183 If latter two parameters are omitted, they will not affect the
184 corresponding SLIP configuration.
185 If any of first two parameters is equal to zero, it will not affect
186 the corresponding SLIP configuration.
192 entry for each legal, remote slip site with
194 as the shell for that entry. E.g.,
196 Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin
199 (Our convention is to name the account used by remote host
203 Then an entry is added to
207 .Bd -literal -offset indent -compact
208 Sfoo `hostname` foo netmask
215 to the local host name and
217 is the local host IP netmask.
221 must be setuid to root and, while not a security hole, moral defectives
222 can use it to place terminal lines in an unusable state and/or deny
223 access to legitimate users of a remote slip line. To prevent this,
229 and mode 4550 so that only members of group
233 The system administrator should make sure that all legitimate users
234 are a member of the correct group.
238 utility logs various information to the system log daemon,
240 with a facility code of
242 The messages are listed here, grouped by severity level.
245 .Bl -tag -width Ds -compact
246 .It Sy ioctl (TCGETS): Em reason
250 to get the line parameters failed.
252 .It Sy ioctl (TCSETS): Em reason
256 to set the line parameters failed.
258 .It Sy /etc/sliphome/slip.hosts: Em reason
260 .Pa /etc/sliphome/slip.hosts
261 file could not be opened.
263 .It Sy access denied for Em user
267 .Pa /etc/sliphome/slip.hosts .
271 .Bl -tag -width Ds -compact
272 .It Sy "attaching slip unit" Em unit Sy for Ar loginname
276 was successfully attached.
279 .Bl -tag -width indent
280 .It Pa /etc/sliphome/slip.hosts
281 list of host login names and parameters.
282 .It Pa /etc/sliphome/slip.login
283 script executed when a connection is made.
284 .It Pa /etc/sliphome/slip.login. Ns Ar loginname
285 script executed when a connection is made by
287 .It Pa /etc/sliphome/slip.logout
288 script executed when a connection is lost.
289 .It Pa /etc/sliphome/slip.logout. Ns Ar loginname
290 script executed when a connection is lost by
292 .It Pa /etc/sliphome/slip.slparms
293 extra parameters file.
294 .It Pa /etc/sliphome/slip.slparms. Ns Ar loginname
295 extra parameters file for
297 .It Pa /var/run/ Ns Ar ttyXn Ns Pa .if
298 contains the name of the network interface used by the sliplogin process on
300 .It Pa /var/run/ Ns Ar slX Ns Pa .pid
301 contains the PID of the sliplogin process which is using interface
308 .Pa /usr/share/examples/sliplogin