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32 .\" @(#)sliplogin.8 8.2 (Berkeley) 1/5/94
39 .Nd attach a serial line network interface
42 .Op Ar loginname Op Ar device
45 is used to turn the terminal line on standard input (or
49 link to a remote host. To do this, the program
51 .Pa /etc/sliphome/slip.hosts
54 (which defaults to the current login name if omitted).
55 If a matching entry is found, the line is configured appropriately
56 for slip (8-bit transparent i/o) and converted to
58 line discipline using the optional line discipline parameters.
60 The optional line discipline parameters consist of one or more of
67 which correspond respectively to
68 .Sq use normal line discipline
69 (no header compression),
70 .Sq enable VJ header compression ,
71 .Sq throw away ICMP packets ,
73 .Sq auto enable VJ header compression
74 (only if the remote end of the link also supports it).
76 Then a shell script is invoked to initialize the slip
77 interface with the appropriate local and remote
82 The usual initialization script is
83 .Pa /etc/sliphome/slip.login
84 but, if particular hosts need special initialization, the file
85 .Pa /etc/sliphome/slip.login. Ns Ar loginname
86 will be executed instead if it exists.
87 The script is invoked with the parameters
88 .Bl -tag -width slipunit
90 The unit number of the slip interface assigned to this line. E.g.,
95 The speed of the line.
97 The arguments from the
98 .Pa /etc/sliphome/slip.hosts
99 entry, in order starting with
103 Only the super-user may attach a network interface. The interface is
104 automatically detached when the other end hangs up or the
106 process dies. If the kernel slip
107 module has been configured for it, all routes through that interface will
108 also disappear at the same time. If there is other processing a site
109 would like done on hangup, the file
110 .Pa /etc/sliphome/slip.logout
112 .Pa /etc/sliphome/slip.logout. Ns Ar loginname
113 is executed if it exists. It is given the same arguments as the login script.
114 .Ss Format of /etc/sliphome/slip.hosts
115 Comments (lines starting with a `#') and blank lines (or started
116 with space) are ignored.
117 Other lines must start with a
119 but the remaining arguments can be whatever is appropriate for the
121 file that will be executed for that name.
122 Arguments are separated by white space and follow normal
124 quoting conventions (however,
127 Usually, lines have the form
128 .Bd -literal -offset indent
129 loginname local-address remote-address netmask opt-args
136 are the IP host names or addresses of the local and remote ends of the
139 is the appropriate IP netmask. These arguments are passed
143 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. If FRAME_END is not received in
165 closes the line and exits.
166 The default value is no timeout (zero).
168 Set SLIP "out fill" timeout in seconds. 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. Use with caution, because no check is made
174 for two interfaces with same number.
175 By default sliplogin dynamically assigns the unit number.
178 If latter two parameters are omitted, they will not affect the
179 corresponding SLIP configuration.
180 If any of first two parameters is equal to zero, it will not affect
181 the corresponding SLIP configuration.
187 entry for each legal, remote slip site with
189 as the shell for that entry. E.g.,
191 Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/usr/sbin/sliplogin
194 (Our convention is to name the account used by remote host
198 Then an entry is added to
202 .Bd -literal -offset indent -compact
203 Sfoo `hostname` foo netmask
210 to the local host name and
212 is the local host IP netmask.
216 must be setuid to root and, while not a security hole, moral defectives
217 can use it to place terminal lines in an unusable state and/or deny
218 access to legitimate users of a remote slip line. To prevent this,
224 and mode 4550 so that only members of group
228 The system administrator should make sure that all legitimate users
229 are a member of the correct group.
232 logs various information to the system log daemon,
234 with a facility code of
236 The messages are listed here, grouped by severity level.
239 .Bl -tag -width Ds -compact
240 .It Sy ioctl (TCGETS): Em reason
244 to get the line parameters failed.
246 .It Sy ioctl (TCSETS): Em reason
250 to set the line parameters failed.
252 .It Sy /etc/sliphome/slip.hosts: Em reason
254 .Pa /etc/sliphome/slip.hosts
255 file could not be opened.
257 .It Sy access denied for Em user
261 .Pa /etc/sliphome/slip.hosts .
265 .Bl -tag -width Ds -compact
266 .It Sy "attaching slip unit" Em unit Sy for Ar loginname
270 was successfully attached.
273 .Ar /etc/sliphome/slip.hosts
274 list of host login names and parameters.
276 .Ar /etc/sliphome/slip.login
277 script executed when a connection is made.
279 .Ar /etc/sliphome/slip.login.loginname
280 script executed when a connection is made by
283 .Ar /etc/sliphome/slip.logout
284 script executed when a connection is lost.
286 .Ar /etc/sliphome/slip.logout.loginname
287 script executed when a connection is lost by
290 .Ar /etc/sliphome/slip.slparms
291 extra parameters file.
293 .Ar /etc/sliphome/slip.slparms.loginname
294 extra parameters file for
297 .Ar /var/run/ttyXn.if
298 contains the name of the network interface used by the sliplogin process on
302 contains the PID of the sliplogin process which is using interface
308 .Pa /usr/share/examples/sliplogin