Provided by: libc-bin_2.15-0ubuntu10_i386
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 get the chance to dynamically change the sorting. For
the glibc implementation this can be achieved with the /etc/gai.conf
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 is present 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 label 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.
This keyword control whether a process checks whether the
configuration file has been changes since the last time it was
read. If the value is `yes' the file is re-read. This might
cause problems in multi-threaded 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
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
Ulrich Drepper <drepper redhat com>
getaddrinfo(3), RFC 3484