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NAME | DESCRIPTION | FILES | VERSIONS | EXAMPLE | SEE ALSO | COLOPHON |
GAI.CONF(5) Linux Programmer's Manual GAI.CONF(5)
gai.conf - getaddrinfo(3) configuration file
A call to getaddrinfo(3) might return multiple answers. According to
RFC 3484 these answers must be sorted so that the answer with the
highest success rate is first in the list. The RFC provides an
algorithm for the sorting. The static rules are not always adequate,
though. For this reason, the RFC also requires that system
administrators should have the possibility to dynamically change the
sorting. For the glibc implementation, this can be achieved with the
/etc/gai.conf file.
Each line in the configuration file consists of a keyword and its
parameters. White spaces in any place are ignored. Lines starting
with '#' are comments and are ignored.
The keywords currently recognized are:
label netmask precedence
The value is added to the label table used in the RFC 3484
sorting. If any label definition is present in the
configuration file, the default table is not used. All the
label definitions of the default table which are to be
maintained have to be duplicated. Following the keyword, the
line has to contain a network mask and a precedence value.
precedence netmask precedence
This keyword is similar to label, but instead the value is
added to the precedence table as specified in RFC 3484. Once
again, the presence of a single precedence line in the
configuration file causes the default table to not be used.
reload <yes|no>
This keyword controls whether a process checks whether the
configuration file has been changed since the last time it was
read. If the value is "yes", the file is reread. This might
cause problems in multithreaded applications and is generally
a bad idea. The default is "no".
scopev4 mask value
Add another rule to the RFC 3484 scope table for IPv4 address.
By default, the scope IDs described in section 3.2 in RFC 3438
are used. Changing these defaults should hardly ever be
necessary.
/etc/gai.conf
The gai.conf file is supported by glibc since version 2.5.
The default table according to RFC 3484 would be specified with the
following configuration file:
label ::1/128 0
label ::/0 1
label 2002::/16 2
label ::/96 3
label ::ffff:0:0/96 4
precedence ::1/128 50
precedence ::/0 40
precedence 2002::/16 30
precedence ::/96 20
precedence ::ffff:0:0/96 10
getaddrinfo(3), RFC 3484
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Linux 2016-03-15 GAI.CONF(5)
Pages that refer to this page: getaddrinfo(3)