  Setting up a domain definition


  11..  TTaasskkss


  A machine may act as a DNS server for several domains at once. It may
  even act as a DNS for domains other than its own.  In fact, it is not
  uncommon to see a server providing DNS services for a completely
  foreign domain.

  To set up a new domain, you must complete a form. Fortunately,
  _L_i_n_u_x_c_o_n_f can set up suitable defaults for all fields except one. Here
  they are:


  22..  DDoommaaiinn nnaammee oorr IIPP rreevveerrssee mmaappppiinngg

  The dialog to create a domain name is similar to the one used to
  create an IP reverse mapping. The first field is either a domain name
  or an IP number.


  22..11..  DDoommaaiinn nnaammee

  You must enter the domain name. A domain name is a series of names
  glued together with dots. For example:


                       solucorp.qc.ca


  can be read as the sub-domain solucorp, part of the sub-domain qc,
  itself part of the top-level domain ca.

  Unless you have an isolated network, you must request an official
  domain name. Say you want to register the domain foo.com, you will
  have to request permission from the authority managing the domain com.
  If later you want to setup the domain sub.foo.com, you will have to
  ask yourself, since you will be the authority of the domain foo.com.

  Your Internet Service Provider will help you to select a proper domain
  name.

  If you are not connected to the Internet, you are free to set up any
  domain you want.


  22..22..  NNeettwwoorrkk nnuummbbeerr

  When setting up a pseudo domain for IP reverse mapping, just enter the
  prefix of the network number. For example, if you are setting an IP
  reverse mapping for network 192.168.1.0, just enter 192.168.1.  You
  can also enter the longer 1.168.192.in-addr.arpa and Linuxconf will
  translate that correctly.


  33..  MMaaiinn sseerrvveerr

  Several machines can act as a DNS for a given domain. One of those
  servers is the _p_r_i_m_a_r_y. All others are backups and are called
  _s_e_c_o_n_d_a_r_i_e_s. The machine where you set up the DNS for a domain is
  normally the main server of that domain, so the default provided
  should be correct.


  44..  AAddmmiinniissttrraattoorr eemmaaiill

  You must provide the email address of the person in charge of the DNS
  for this domain. An alias is acceptable, but make sure it effectively
  points to someone. This email address can be queried using the DNS
  itself, so it is useful information.


  55..  DDNNSS aaddvveerrttiissiinngg

  You must define here the list of DNSs (primary and backups) serving
  this domain. You will probably enter the fully qualified name of this
  machine and all secondary DNSs.


  66..  EEMMAAIILL aaddvveerrttiissiinngg

  You can define which host is responsible for collecting mail for the
  entire domain. This host may be unrelated to the domain itself. Of
  course, it must be configured to relay the messages to the proper mail
  server of your domain.

  You can define a backup for this host. If the host is not reachable,
  email will be automatically forwarded to the backup hosts.


  77..  DDeeffaauulltt IIPPss

  One popular practice is to assign an IP number (or more than one) to a
  domain itself. For example, many sysadmins will assign the same IP
  number to the Web server of a domain and to the domain itself. This
  allows one to browse your domain's website with http://www.domain.com
  or simply http://domain.com.

  _L_i_n_u_x_c_o_n_f allows you to set the default IPs of the domain right here.
  If you do so, it will enter the proper records in the DNS, but it
  won't modify the reverse mappings of the IP numbers. This means that
  two following commands, for example:


               nslookup domain.com
               nslookup www.domain.com


  will produce the same result (the same IP numbers). But if one types


               nslookup The_IP_number_of_www.domain.com


  one will get www.domain.com as the result and not simply domain.com.


  88..  SSeeccoonnddaarriieess rreeqquuiirreemmeennttss

  Secondaries are DNS machines which take a copy of selective domains of
  your DNS. Secondaries must be defined in the parent domain.