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       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




       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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