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d97d06f7 | 1 | .\" Copyright (C) 2006 Red Hat, Inc. All rights reserved. |
4016e7fb | 2 | .\" Author: Ulrich Drepper <drepper@redhat.com> |
d97d06f7 | 3 | .\" |
ef06249a | 4 | .\" %%%LICENSE_START(GPLv2_MISC) |
d97d06f7 UD |
5 | .\" This copyrighted material is made available to anyone wishing to use, |
6 | .\" modify, copy, or redistribute it subject to the terms and conditions of the | |
7 | .\" GNU General Public License v.2. | |
8 | .\" | |
9 | .\" This program is distributed in the hope that it will be useful, but WITHOUT | |
10 | .\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | .\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | .\" more details. | |
13 | .\" | |
c715f741 MK |
14 | .\" You should have received a copy of the GNU General Public |
15 | .\" License along with this manual; if not, see | |
16 | .\" <http://www.gnu.org/licenses/>. | |
8ff7380d | 17 | .\" %%%LICENSE_END |
d97d06f7 | 18 | .\" |
aafcfc16 | 19 | .TH GAI.CONF 5 2013-02-13 "Linux" "Linux Programmer's Manual" |
d97d06f7 UD |
20 | .SH NAME |
21 | gai.conf \- getaddrinfo(3) configuration file | |
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22 | .SH DESCRIPTION |
23 | A call to | |
24 | .BR getaddrinfo (3) | |
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25 | might return multiple answers. |
26 | According to RFC\ 3484 these answers must be sorted so that | |
27 | the answer with the highest success rate is first in the list. | |
28 | The RFC provides an algorithm for the sorting. | |
29 | The static rules are not always adequate, though. | |
30 | For this reason, | |
31 | the RFC also requires that system administrators should have the possibility | |
32 | to dynamically change the sorting. | |
33 | For the glibc implementation, this can be achieved with the | |
34 | .IR /etc/gai.conf | |
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35 | file. |
36 | .PP | |
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37 | Each line in the configuration file consists of a keyword and its parameters. |
38 | White spaces in any place are ignored. | |
39 | Lines starting with \(aq#\(aq are comments and are ignored. | |
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40 | .PP |
41 | The keywords currently recognized are: | |
42 | .TP | |
43 | \fBlabel\fR \fInetmask\fR \fIprecedence\fR | |
5f86385e | 44 | The value is added to the label table used in the RFC\ 3484 sorting. |
e23f2a23 RI |
45 | If any \fBlabel\fR definition is present in the configuration file, |
46 | the default table is not used. | |
5f86385e | 47 | All the label definitions |
d97d06f7 | 48 | of the default table which are to be maintained have to be duplicated. |
5f86385e | 49 | Following the keyword, |
e23f2a23 | 50 | the line has to contain a network mask and a precedence value. |
d97d06f7 UD |
51 | .TP |
52 | \fBprecedence\fR \fInetmask\fR \fIprecedence\fR | |
3d1ee497 | 53 | This keyword is similar to \fBlabel\fR, but instead the value is added |
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54 | to the precedence table as specified in RFC\ 3484. |
55 | Once again, the | |
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56 | presence of a single \fBprecedence\fR line in the configuration file |
57 | causes the default table to not be used. | |
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58 | .TP |
59 | \fBreload\fR <\fByes\fR|\fBno\fR> | |
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60 | This keyword controls whether a process checks whether the configuration |
61 | file has been changed since the last time it was read. | |
62 | If the value is | |
62418352 | 63 | "\fByes\fR", the file is reread. |
a2e992fe | 64 | This might cause problems in multithreaded |
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65 | applications and is generally a bad idea. |
66 | The default is "\fBno\fR". | |
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67 | .TP |
68 | \fBscopev4\fR \fImask\fR \fIvalue\fR | |
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69 | Add another rule to the RFC\ 3484 scope table for IPv4 address. |
70 | By default, the scope IDs described in section 3.2 in RFC\ 3438 are used. | |
d97d06f7 | 71 | Changing these defaults should hardly ever be necessary. |
5f86385e MK |
72 | .SH FILES |
73 | \fI/etc/gai.conf\fR | |
d97d06f7 | 74 | .SH EXAMPLE |
5f86385e | 75 | The default table according to RFC\ 3484 would be specified with the |
d97d06f7 UD |
76 | following configuration file: |
77 | ||
78 | .nf | |
79 | label ::1/128 0 | |
80 | label ::/0 1 | |
81 | label 2002::/16 2 | |
82 | label ::/96 3 | |
83 | label ::ffff:0:0/96 4 | |
84 | precedence ::1/128 50 | |
85 | precedence ::/0 40 | |
86 | precedence 2002::/16 30 | |
87 | precedence ::/96 20 | |
88 | precedence ::ffff:0:0/96 10 | |
5f86385e | 89 | .fi |
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90 | .\" .SH AUTHOR |
91 | .\" Ulrich Drepper <drepper@redhat.com> | |
b072a788 | 92 | .\" |
d97d06f7 | 93 | .SH SEE ALSO |
5dbf5d5b | 94 | .BR getaddrinfo (3), |
5f86385e | 95 | RFC\ 3484 |