File: tcprules.1

package info (click to toggle)
ucspi-tcp-src 0.88-15
  • links: PTS
  • area: non-free
  • in suites: lenny, squeeze
  • size: 1,380 kB
  • ctags: 761
  • sloc: ansic: 6,758; makefile: 854; sh: 312
file content (221 lines) | stat: -rw-r--r-- 3,581 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
.TH tcprules 1
.SH NAME
tcprules \- compile rules for tcpserver
.SH SYNOPSIS
.B tcprules
.I rules.cdb
.I rules.tmp
.SH OVERVIEW
.B tcpserver
optionally follows rules to decide whether a TCP connection is acceptable.
For example, a rule of

.EX
   18.23.0.32:deny
.EE

prohibits connections from IP address 18.23.0.32.

.B tcprules
reads rules from its standard input
and writes them into
.I rules.cdb
in a binary format suited
for quick access by
.BR tcpserver .

.B tcprules
can be used while
.B tcpserver
is running:
it ensures that
.I rules.cdb
is updated atomically.
It does this by first writing the rules to
.I rules.tmp
and then moving
.I rules.tmp
on top of
.IR rules.cdb .
If
.I rules.tmp
already exists, it is destroyed.
The directories containing
.I rules.cdb
and
.I rules.tmp
must be writable to
.BR tcprules ;
they must also be on the same filesystem.

If there is a problem with the input,
.B tcprules
complains and leaves
.I rules.cdb
alone.

The binary
.I rules.cdb
format is portable across machines.
.SH "RULE FORMAT"
A rule takes up one line.
A file containing rules
may also contain comments: lines beginning with # are ignored.

Each rule contains an
.BR address ,
a colon,
and a list of
.BR instructions ,
with no extra spaces.
When
.B tcpserver
receives a connection from that address,
it follows the instructions.
.SH "ADDRESSES"
.B tcpserver
starts by looking for a rule with address
.IR TCPREMOTEINFO\fB@\fITCPREMOTEIP .
If it doesn't find one, or if
.I TCPREMOTEINFO
is not set, it tries the address
.IR TCPREMOTEIP .
If that doesn't work, it tries shorter and shorter prefixes of
.I TCPREMOTEIP
ending with a dot.
If none of them work, it tries the empty string.

For example, here are some rules:

.EX
   joe@127.0.0.1:first
.br
   18.23.0.32:second
.br
   127.:third
.br
   :fourth
.br
   ::1:fifth
.EE

If
.I TCPREMOTEIP
is
.BR 10.119.75.38 ,
.B tcpserver
will follow the
.B fourth
instructions.

If
.I TCPREMOTEIP
is
.BR ::1 ,
.B tcpserver
will follow the
.B fifth
instructions.  Note that you cannot detect IPv4 mapped addresses by
matching "::ffff", as those addresses will be converted to IPv4 before
looking at the rules.

If
.I TCPREMOTEIP
is
.BR 18.23.0.32 ,
.B tcpserver
will follow the
.B second
instructions.

If
.I TCPREMOTEINFO
is
.B bill
and
.I TCPREMOTEIP
is
.BR 127.0.0.1 ,
.B tcpserver
will follow the
.B third
instructions.

If
.I TCPREMOTEINFO
is
.B joe
and
.I TCPREMOTEIP
is
.BR 127.0.0.1 ,
.B tcpserver
will follow the
.B first
instructions.
.SH "ADDRESS RANGES"
.B tcprules
treats
.B 1.2.3.37-53:ins
as an abbreviation
for the rules
.BR 1.2.3.37:ins ,
.BR 1.2.3.38:ins ,
and so on up through
.BR 1.2.3.53:ins .
Similarly,
.BR 10.2-3.:ins
is an abbreviation for
.B 10.2.:ins
and
.BR 10.3.:ins .
.SH "INSTRUCTIONS"
The instructions in a rule must begin with either
.B allow
or
.BR deny .
.B deny
tells
.B tcpserver
to drop the connection without running anything.
For example, the rule

.EX
   :deny
.EE

tells
.B tcpserver
to drop all connections that aren't handled by more specific rules.

The instructions may continue with some environment variables,
in the format
.IR ,VAR="VALUE" .
.B tcpserver
adds
.I VAR=VALUE
to the current environment.
For example,

.EX
   10.0.:allow,RELAYCLIENT="@fix.me"
.EE

adds
.B RELAYCLIENT=@fix.me
to the environment.
The quotes here may be replaced by any repeated character:

.EX
   10.0.:allow,RELAYCLIENT=/@fix.me/
.EE

Any number of variables may be listed:

.EX
   127.0.0.1:allow,RELAYCLIENT="",TCPLOCALHOST="movie.edu"
.EE
.SH "SEE ALSO"
tcprulescheck(1),
tcpserver(1),
tcp-environ(5)