Provided by: nslint_3.0a2-1.1build1_amd64 bug


       nslint - perform consistency checks on dns files


       nslint [ -d ] [ -c named.conf ] [ -C nslint.conf ]
       nslint [ -d ] [ -b named.boot ] [ -B nslint.boot ]


       Nslint  reads  the  nameserver  configuration  files  and performs a number of consistency
       checks on the dns records. If any problems are discovered, error messages are displayed on
       stderr and nslint exits with a non-zero status.

       Here is a partial list of errors nslint detects:

              Records that are malformed.

              Names that contain dots but are missing a trailing dot.

              PTR records with names that are missing a trailing dot.

              Names that contain illegal characters (rfc1034).

              A records without matching PTR records

              PTR records without matching A records

              Names with more than one address on the same subnet.

              Addresses in use by more than one name.

              Names with CNAME and other records (rfc1033).

              Unknown service and/or protocol keywords in WKS records.

              Missing semicolons and quotes.


       -b     Specify an alternate named.boot file. The default is /etc/named.boot.

       -c     Specify an alternate named.conf file. The default is /etc/named.conf.

       -B     Specify  an  alternate  nslint.boot  file.  The  default is nslint.boot in the last
              directory line processed in named.boot (or the current  working  directory).   This
              file  is processed like a second named.boot.  The most common use is to tell nslint
              about A records that match PTR records that point outside  the  domains  listed  in

       -C     Specify  an  alternate  nslint.conf  file.  The  default is nslint.conf in the last
              directory line processed in named.conf (or the current  working  directory).   This
              file is processed like a second named.conf.

       -d     Raise the debugging level. Debugging information is displayed on stdout.

       Nslint  knows  how  to  read  BIND  8 and 9's named.conf configuration file and also older
       BIND's named.boot file. If both files exist, nslint will prefer named.conf (on the  theory
       that you forgot to delete named.boot when you upgraded BIND).


       There  are  some cases where it is necessary to use the advanced configuration features of
       nslint.  Advanced configuration is done with the  nslint.conf  file.  (You  can  also  use
       nslint.boot which has a syntax similar to named.boot but is not described here.)

       The  most  common is when a site has a demilitarized zone (DMZ).  The problem here is that
       the DMZ network will have PTR records for hosts outside its domain. For example  lets  say
       we have 128.0.rev with:

              1.1     604800  in      ptr
              2.1     604800  in      ptr

       Obviously we will define an A record for pointing to but we will
       get errors because there is no A record defined for  The  solution  is  to
       create a nslint.conf file (in the same directory as the other dns files) with:

              zone "" {
                     type master;
                     file "";

       And then create the file with:

              gateway 1       in      a

       Another  problem  occurs  when  there  is  a CNAME that points to a host outside the local
       domains. Let's say we have pointing to

              info    604800  in      cname

       In this case we would need:

              zone "" {
                     type master;
                     file "";

       in nslint.boot and:

              larry   1       in      txt     "place holder"

       One last problem when a pseudo host is setup to allow two more more actual hosts provide a
       service. For, let's say that contains:

              server  604800  in      a
              server  604800  in      a
              tom     604800  in      a
              tom     604800  in      mx 0
              jerry   604800  in      a
              jerry   604800  in      mx 0

       In  this  case  nslint would complain about missing PTR records and ip addresses in use by
       more than one host.  To suppress these warnings, add you would the lines:

              zone "" {
                     type master;
                     file "";

              zone "" {
                     type master;
                     file "nslint.128.0.rev";

       to nslint.conf and create with:

              server  1       in      allowdupa
              server  1       in      allowdupa

       and create nslint.128.0.rev with:

              6.6     604800  in      ptr
              94.6    604800  in      ptr

       In this example, the allowdupa keyword  tells  nslint  that  it's  ok  for  and to be shared by,, and

       Another  nslint  feature  helps  detect  hosts  that  have mistakenly had two ip addresses
       assigned on the same subnet. This can happen when  two  different  people  request  an  ip
       address  for  the  same  hostname or when someone forgets an address has been assigned and
       requests a new number.

       To detect such A records, add a nslint section to your  nslint.conf  containing  something
       similar to:

              nslint {
                     network "128.0.6/22";


              nslint {
                     network "128.0.6";

       These  two  examples are are equivalent ways of saying the same thing; that subnet 128.0.6
       has a 22 bit wide subnet mask.

       Using information from the above network statement, nslint would would flag the  following
       A records as being in error:

              server  1       in      a
              server  1       in      a

       Note  that  if you specify any network lines in your nslint.conf file, nslint requires you
       to include lines for all networks; otherwise you might forget to add network lines for new

       Sometimes  you  have  a zone that nslint just can't deal with. A good example is a dynamic
       dns zone. To handle this, you can add the following to

              nslint {
                     ignorezone "";

       This will suppress "name referenced without other records" warnings.


       /etc/named.conf - default named configuration file
       /etc/named.boot - old style named configuration file
       nslint.conf - default nslint configuration file
       nslint.boot - old style nslint configuration file


       named(8), rfc1033, rfc1034


       Craig Leres of the  Lawrence  Berkeley  National  Laboratory,  University  of  California,
       Berkeley, CA.

       The current version is available via anonymous ftp:



       Please send bug reports to

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