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28 .\" @(#)sliplogin.8 8.2 (Berkeley) 1/5/94
29 .\" $FreeBSD: src/usr.sbin/sliplogin/sliplogin.8,v 1.12.2.5 2003/03/11 22:31:33 trhodes Exp $
30 .\" $DragonFly: src/usr.sbin/sliplogin/sliplogin.8,v 1.4 2006/04/17 18:01:38 swildner Exp $
37 .Nd attach a serial line network interface
40 .Op Ar loginname Op Ar device
44 utility is used to turn the terminal line on standard input (or
48 link to a remote host. To do this, the program
50 .Pa /etc/sliphome/slip.hosts
53 (which defaults to the current login name if omitted).
54 If a matching entry is found, the line is configured appropriately
55 for slip (8-bit transparent i/o) and converted to
57 line discipline using the optional line discipline parameters.
59 The optional line discipline parameters consist of one or more of
66 which correspond respectively to
67 .Sq use normal line discipline
68 (no header compression),
69 .Sq enable VJ header compression ,
70 .Sq throw away ICMP packets ,
72 .Sq auto enable VJ header compression
73 (only if the remote end of the link also supports it).
75 Then a shell script is invoked to initialize the slip
76 interface with the appropriate local and remote
81 The usual initialization script is
82 .Pa /etc/sliphome/slip.login
83 but, if particular hosts need special initialization, the file
84 .Pa /etc/sliphome/slip.login. Ns Ar loginname
85 will be executed instead if it exists.
86 The script is invoked with the parameters
87 .Bl -tag -width slipunit
89 The unit number of the slip interface assigned to this line. E.g.,
94 The speed of the line.
96 The arguments from the
97 .Pa /etc/sliphome/slip.hosts
98 entry, in order starting with
102 Only the super-user may attach a network interface. The interface is
103 automatically detached when the other end hangs up or the
105 process dies. If the kernel slip
106 module has been configured for it, all routes through that interface will
107 also disappear at the same time. If there is other processing a site
108 would like done on hangup, the file
109 .Pa /etc/sliphome/slip.logout
111 .Pa /etc/sliphome/slip.logout. Ns Ar loginname
112 is executed if it exists. It is given the same arguments as the login script.
113 .Ss Format of /etc/sliphome/slip.hosts
114 Comments (lines starting with a `#') and blank lines (or started
115 with space) are ignored.
116 Other lines must start with a
118 but the remaining arguments can be whatever is appropriate for the
120 file that will be executed for that name.
121 Arguments are separated by white space and follow normal
123 quoting conventions (however,
126 Usually, lines have the form
127 .Bd -literal -offset indent
128 loginname local-address remote-address netmask opt-args
135 are the IP host names or addresses of the local and remote ends of the
138 is the appropriate IP netmask. These arguments are passed
142 are optional arguments used to configure the line.
143 .Sh FreeBSD Additions
144 An additional SLIP configuration file (if present) is
145 .Pa /etc/sliphome/slip.slparms .
146 If particular hosts need different configurations, the file
147 .Pa /etc/sliphome/slip.slparms. Ns Ar loginname
148 will be parsed instead if it exists.
149 .Ss Format of /etc/sliphome/slip.slparms*
150 Comments (lines starting with a `#') and blank lines (or started with
152 This file contains from one to three numeric parameters separated with spaces,
158 .Bl -tag -width keepalive
160 Set SLIP "keep alive" timeout in seconds.
161 If FRAME_END is not received in
164 closes the line and exits.
165 The default value is no timeout (zero).
167 Set SLIP "out fill" timeout in seconds.
168 It forces at least one FRAME_END
169 to be sent during this time period, which is necessary for the "keep alive"
170 timeout on the remote side.
171 The default value is no timeout (zero).
173 Set the SLIP unit number directly.
174 Use with caution, because no check is made
175 for two interfaces with same number.
176 By default sliplogin dynamically assigns the unit number.
179 If latter two parameters are omitted, they will not affect the
180 corresponding SLIP configuration.
181 If any of first two parameters is equal to zero, it will not affect
182 the corresponding SLIP configuration.
184 .Bl -tag -width indent
185 .It Pa /etc/sliphome/slip.hosts
186 list of host login names and parameters.
187 .It Pa /etc/sliphome/slip.login
188 script executed when a connection is made.
189 .It Pa /etc/sliphome/slip.login. Ns Ar loginname
190 script executed when a connection is made by
192 .It Pa /etc/sliphome/slip.logout
193 script executed when a connection is lost.
194 .It Pa /etc/sliphome/slip.logout. Ns Ar loginname
195 script executed when a connection is lost by
197 .It Pa /etc/sliphome/slip.slparms
198 extra parameters file.
199 .It Pa /etc/sliphome/slip.slparms. Ns Ar loginname
200 extra parameters file for
202 .It Pa /var/run/ Ns Ar ttyXn Ns Pa .if
203 contains the name of the network interface used by the sliplogin process on
205 .It Pa /var/run/ Ns Ar slX Ns Pa .pid
206 contains the PID of the sliplogin process which is using interface
214 entry for each legal, remote slip site with
216 as the shell for that entry. E.g.,
218 Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin
221 (Our convention is to name the account used by remote host
225 Then an entry is added to
229 .Bd -literal -offset indent -compact
230 Sfoo `hostname` foo netmask
237 to the local host name and
239 is the local host IP netmask.
243 must be setuid to root and, while not a security hole, moral defectives
244 can use it to place terminal lines in an unusable state and/or deny
245 access to legitimate users of a remote slip line. To prevent this,
251 and mode 4550 so that only members of group
255 The system administrator should make sure that all legitimate users
256 are a member of the correct group.
260 utility logs various information to the system log daemon,
262 with a facility code of
264 The messages are listed here, grouped by severity level.
267 .Bl -tag -width Ds -compact
268 .It Sy ioctl (TCGETS): Em reason
272 to get the line parameters failed.
274 .It Sy ioctl (TCSETS): Em reason
278 to set the line parameters failed.
280 .It Sy /etc/sliphome/slip.hosts: Em reason
282 .Pa /etc/sliphome/slip.hosts
283 file could not be opened.
285 .It Sy access denied for Em user
289 .Pa /etc/sliphome/slip.hosts .
293 .Bl -tag -width Ds -compact
294 .It Sy "attaching slip unit" Em unit Sy for Ar loginname
298 was successfully attached.
304 .Pa /usr/share/examples/sliplogin