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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 $
40 .Nd attach a serial line network interface
43 .Op Ar loginname Op Ar device
47 utility is used to turn the terminal line on standard input (or
51 link to a remote host. To do this, the program
53 .Pa /etc/sliphome/slip.hosts
56 (which defaults to the current login name if omitted).
57 If a matching entry is found, the line is configured appropriately
58 for slip (8-bit transparent i/o) and converted to
60 line discipline using the optional line discipline parameters.
62 The optional line discipline parameters consist of one or more of
69 which correspond respectively to
70 .Sq use normal line discipline
71 (no header compression),
72 .Sq enable VJ header compression ,
73 .Sq throw away ICMP packets ,
75 .Sq auto enable VJ header compression
76 (only if the remote end of the link also supports it).
78 Then a shell script is invoked to initialize the slip
79 interface with the appropriate local and remote
84 The usual initialization script is
85 .Pa /etc/sliphome/slip.login
86 but, if particular hosts need special initialization, the file
87 .Pa /etc/sliphome/slip.login. Ns Ar loginname
88 will be executed instead if it exists.
89 The script is invoked with the parameters
90 .Bl -tag -width slipunit
92 The unit number of the slip interface assigned to this line. E.g.,
97 The speed of the line.
99 The arguments from the
100 .Pa /etc/sliphome/slip.hosts
101 entry, in order starting with
105 Only the super-user may attach a network interface. The interface is
106 automatically detached when the other end hangs up or the
108 process dies. If the kernel slip
109 module has been configured for it, all routes through that interface will
110 also disappear at the same time. If there is other processing a site
111 would like done on hangup, the file
112 .Pa /etc/sliphome/slip.logout
114 .Pa /etc/sliphome/slip.logout. Ns Ar loginname
115 is executed if it exists. It is given the same arguments as the login script.
116 .Ss Format of /etc/sliphome/slip.hosts
117 Comments (lines starting with a `#') and blank lines (or started
118 with space) are ignored.
119 Other lines must start with a
121 but the remaining arguments can be whatever is appropriate for the
123 file that will be executed for that name.
124 Arguments are separated by white space and follow normal
126 quoting conventions (however,
129 Usually, lines have the form
130 .Bd -literal -offset indent
131 loginname local-address remote-address netmask opt-args
138 are the IP host names or addresses of the local and remote ends of the
141 is the appropriate IP netmask. These arguments are passed
145 are optional arguments used to configure the line.
146 .Sh FreeBSD Additions
147 An additional SLIP configuration file (if present) is
148 .Pa /etc/sliphome/slip.slparms .
149 If particular hosts need different configurations, the file
150 .Pa /etc/sliphome/slip.slparms. Ns Ar loginname
151 will be parsed instead if it exists.
152 .Ss Format of /etc/sliphome/slip.slparms*
153 Comments (lines starting with a `#') and blank lines (or started with
155 This file contains from one to three numeric parameters separated with spaces,
161 .Bl -tag -width keepalive
163 Set SLIP "keep alive" timeout in seconds.
164 If FRAME_END is not received in
167 closes the line and exits.
168 The default value is no timeout (zero).
170 Set SLIP "out fill" timeout in seconds.
171 It forces at least one FRAME_END
172 to be sent during this time period, which is necessary for the "keep alive"
173 timeout on the remote side.
174 The default value is no timeout (zero).
176 Set the SLIP unit number directly.
177 Use with caution, because no check is made
178 for two interfaces with same number.
179 By default sliplogin dynamically assigns the unit number.
182 If latter two parameters are omitted, they will not affect the
183 corresponding SLIP configuration.
184 If any of first two parameters is equal to zero, it will not affect
185 the corresponding SLIP configuration.
191 entry for each legal, remote slip site with
193 as the shell for that entry. E.g.,
195 Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin
198 (Our convention is to name the account used by remote host
202 Then an entry is added to
206 .Bd -literal -offset indent -compact
207 Sfoo `hostname` foo netmask
214 to the local host name and
216 is the local host IP netmask.
220 must be setuid to root and, while not a security hole, moral defectives
221 can use it to place terminal lines in an unusable state and/or deny
222 access to legitimate users of a remote slip line. To prevent this,
228 and mode 4550 so that only members of group
232 The system administrator should make sure that all legitimate users
233 are a member of the correct group.
237 utility logs various information to the system log daemon,
239 with a facility code of
241 The messages are listed here, grouped by severity level.
244 .Bl -tag -width Ds -compact
245 .It Sy ioctl (TCGETS): Em reason
249 to get the line parameters failed.
251 .It Sy ioctl (TCSETS): Em reason
255 to set the line parameters failed.
257 .It Sy /etc/sliphome/slip.hosts: Em reason
259 .Pa /etc/sliphome/slip.hosts
260 file could not be opened.
262 .It Sy access denied for Em user
266 .Pa /etc/sliphome/slip.hosts .
270 .Bl -tag -width Ds -compact
271 .It Sy "attaching slip unit" Em unit Sy for Ar loginname
275 was successfully attached.
278 .Bl -tag -width indent
279 .It Pa /etc/sliphome/slip.hosts
280 list of host login names and parameters.
281 .It Pa /etc/sliphome/slip.login
282 script executed when a connection is made.
283 .It Pa /etc/sliphome/slip.login. Ns Ar loginname
284 script executed when a connection is made by
286 .It Pa /etc/sliphome/slip.logout
287 script executed when a connection is lost.
288 .It Pa /etc/sliphome/slip.logout. Ns Ar loginname
289 script executed when a connection is lost by
291 .It Pa /etc/sliphome/slip.slparms
292 extra parameters file.
293 .It Pa /etc/sliphome/slip.slparms. Ns Ar loginname
294 extra parameters file for
296 .It Pa /var/run/ Ns Ar ttyXn Ns Pa .if
297 contains the name of the network interface used by the sliplogin process on
299 .It Pa /var/run/ Ns Ar slX Ns Pa .pid
300 contains the PID of the sliplogin process which is using interface
307 .Pa /usr/share/examples/sliplogin