RESOLVCONF(8)                     resolvconf                     RESOLVCONF(8)



NAME
       resolvconf - manage nameserver information

SYNOPSIS
       cat FILE | resolvconf -a INTERFACE

       resolvconf -d INTERFACE

       resolvconf -u

DESCRIPTION
       Overwrite  (-a)  or  delete  (-d) the nameserver information record for
       network interface INTERFACE and run the update scripts in  /etc/resolv‐
       conf/update.d/ if the nameserver information has changed.

       With -u, just run the update scripts.

SERVERS
       Normally  resolvconf  is  run  only by hook scripts attached to network
       interface configurers such as pppd(8) (for  ppp  interfaces),  to  DHCP
       clients  such as dhclient3(8), to ifup(8) and ifdown, and to DNS caches
       such as dnsmasq(8) (for the loopback interface).  However, the adminis‐
       trator  can  also run resolvconf from the command line to add or delete
       auxiliary nameserver information.

CLIENTS
       Nameserver information provided to resolvconf is stored for use by sub‐
       scribers  to  resolvconf’s notification service.  Subscribers that need
       to know when nameserver information has changed should install a script
       in /etc/resolvconf/update.d/ (... or in /etc/resolvconf/update-libc.d/:
       see below).  For example, DNS caches such as  dnsmasq(8)  and  pdnsd(8)
       subscribe to the notification service so that they know whither to for‐
       ward queries.

       The most important piece of software that subscribes to  the  notifica‐
       tion  service  is  the  set of functions that make up the GNU C Library
       resolver(3).   When  nameserver  information  is  updated  the   script
       /etc/resolvconf/update.d/libc  writes a new resolver configuration file
       to  /etc/resolvconf/run/resolv.conf  and  then  runs  the  scripts   in
       /etc/resolvconf/update-libc.d/.   To  make the resolver use the dynami‐
       cally generated resolver configuration file  the  administrator  should
       ensure  that  /etc/resolv.conf  is  a  symbolic  link  to  /etc/resolv‐
       conf/run/resolv.conf.  This link is never modified by /sbin/resolvconf.
       If  you  find  that /etc/resolv.conf is not being updated, check to see
       that the link is intact.

       The GNU C Library resolver library  isn’t  the  only  resolver  library
       available.   However,  any resolver library that reads /etc/resolv.conf
       (and most of them do, in order to be compatible with the GNU C  Library
       resolver) should work with resolvconf.

       Subscribers that need to know only when the resolver configuration file
       has changed should install a script  in  /etc/resolvconf/update-libc.d/
       rather  than in /etc/resolvconf/update.d/.  (This is important for syn‐
       chronization  purposes:  scripts  in  update-libc.d/  are   run   after
       resolv.conf  has  been  updated;  the  same  is not necessarily true of
       scripts in update.d/.)  Examples of packages that do  this  are  fetch�‐
       mail(1) and squid(8).

       Hook  scripts  will find the files containing nameserver information in
       the current directory.

OPTIONS
       -a INTERFACE
              Add or overwrite the record  for  network  interface  INTERFACE.
              When  this  option  is  used the information must be provided to
              resolvconf  on  its  standard  input  in  the  format   of   the
              resolv.conf(5)  file.   Each line in the file must be terminated
              by a newline.

       -d INTERFACE
              Delete the record for network interface INTERFACE.

       The INTERFACE name may not contain spaces,  slashes  or  initial  dots,
       hyphens or tildes.

       Following  the  addition or deletion of the record, resolvconf runs the
       update scripts as described in the CLIENTS section.

       -u     Just run the update scripts.

FILES
       /etc/resolvconf/run
              This is either a directory where nameserver information  can  be
              stored  or  a symbolic link to such a directory.  Clients should
              not make any assumptions about the canonical  location  of  this
              directory or the hierarchy that is constructed under it.

       /etc/resolvconf/interface-order
              Determines the order in which nameserver information records are
              processed.  See interface-order(5).

       /etc/resolvconf/resolv.conf.d/base
              File containing basic resolver information.  The lines  in  this
              file  are  included in the resolver configuration file even when
              no interfaces are configured.

       /etc/resolvconf/resolv.conf.d/head
              File to be prepended to the dynamically generated resolver  con‐
              figuration file.  Normally this is just a comment line.

       /etc/resolvconf/resolv.conf.d/tail
              File  to  be appended to the dynamically generated resolver con‐
              figuration file.  To append nothing, make this an empty file.

BUGS
       Currently resolvconf does not check the sanity of the information  pro‐
       vided to it.

AUTHOR
       Written by Thomas Hood <jdthood@yahoo.co.uk>.

COPYRIGHT
       Copyright © 2004 Thomas Hood
       This is free software; see the source for copying conditions.  There is
       NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR
       PURPOSE.

SEE ALSO
       interface-order(5), resolv.conf(5), resolver(3).



resolvconf                        April 2005                     RESOLVCONF(8)