  IP Allocation Conflict Resolution


  Normally, DNS associates a single name with a given IP address. A
  reverse search is possible, which allows one to find the name from the
  IP. It is sometimes convenient (or even necessary) to have more than
  one name, sharing a given IP number. A common case is a default IP
  associated with a domain. This default IP is generally the IP number
  of the Web server, making it convenient for Web users. _L_i_n_u_x_c_o_n_f is
  trying to flag duplicate usage and help you manage your DNS properly.

  11..  NNoorrmmaall ooppeerraattiioonn

  When updating a definition for a host name in a domain, Linuxconf
  verifies that the IPs allocated are not already in use by another host
  managed by this DNS. If there is no other host using that (those)
  IP(s), Linuxconf will update the various records, including the
  reverse mappings (PTR records).

  If there is a conflict, a dialog is presented which allows full
  control over Linuxconf's behavior.


  22..  SSoo tthheerree iiss aa ccoonnfflliicctt

  What are your options when there are such conflicts?  When more than
  one host is sharing one IP number, one is known as the official host
  and the reverse mapping points to it. Therefore, you mostly have this
  DNS relation:


               host.domain -> IP number
               IP number   -> host.domain


  All other host names sharing the IP will only have the first line of
  this relation. Linuxconf enforces this. So when there is a conflict
  your options are:


  +o  Cancel the dialog and pick another IP number

  +o  Tell linuxconf that this host is the "main" one so linuxconf will
     use this host name to do the reverse mapping (and will delete any
     previous reverse mapping on this IP number).

  +o  Tell linuxconf that this host is not the "main" one. Linuxconf
     won't update the reverse mapping.


  33..  TThhee IIPP aallllooccaattiioonn ccoonnfflliicctt rreessoolluuttiioonn  ddiiaalloogg

  You are allowed to enter up to four IP numbers per host name.  If
  there is a conflict for at least one IP number, Linuxconf will present
  you with a dialog, showing you each IP number and the suggested update
  mode. Linuxconf may or may not update the reverse mapping associated
  with each IP number.

  The dialog appears with a checkbox for each IP number. Those with a
  conflict, have unchecked checkboxes. This means that if you simply
  "accept" the dialog as is, Linuxconf won't update the reverse mapping
  of the IP numbers where there is a conflict.
  By checking or unchecking the checkbox, you effectively tell linuxconf
  to update, or leave unchanged, the reverse lookup for the given IP.


  44..  EEnntteerriinngg aann IIPP nnuummbbeerr ffoorr aa ddoommaaiinn

  Since this is common practice and a reverse mapping pointing to a
  domain is a bad practice (it must point to a _h_o_s_t of the domain),
  linuxconf does not signal any conflict when entering IP numbers for a
  domain. (There should be a conflict indeed!)