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       axfr-get - a DNS zone-transfer client.

       It  sends  a zone-transfer request in DNS-over-TCP format to descriptor
       7, reads the results from descriptor 6, and  saves  the  results  in  a


       Normally  axfr-get is run under tcpclient(1), which sets up descriptors
       6 and 7 as a TCP connection to a remote host.

       axfr-get z fn fn.tmp


       axfr-get performs a zone transfer for domain z.  It writes the  results
       to fn.tmp in a format that can be used as input to tinydns-data(8).  If
       the zone transfer completes successfully, axfr-get  atomically  renames
       fn.tmp as fn.

       fn.tmp and fn must be on the same filesystem.

       axfr-get  writes  the  zone  serial  number  as a comment at the top of
       fn.tmp.  It skips the zone transfer, leaving fn alone,  if  fn  already

       fn has a serial number matching the zone serial number, and both serial
       numbers are nonzero.

       Zone transfers often include duplicate records.  You  should  feed  the
       axfr-get results through sort -u.

       axfr-get discards all records outside the domain z.  It accepts records
       in child zones, but it marks all child zones as  non-authoritative,  so
       tinydns(8)  will  not report those records except as glue.  If you plan
       to merge the axfr-get results for a domain and  a  child  of  the  same
       domain,  creating  a  file  authoritative  for both zones, make sure to
       eliminate records in the first output that are within the child zone.

       axfr-get will accept arbitrarily large zone transfers.   To  limit  the
       maximum  file  size  to  1  megabyte,  run  axfr-get under softlimit -f

Compatibility notes

       axfr-get  handles  BIND’s  RFC-1034-violating  multiple-answers   zone-
       transfer format.

       axfr-get  does  not precisely simulate BIND’s handling of *.dom.  Under
       BIND, records for *.dom do not apply  to  y.dom  or  anything.y.dom  if
       there  is  a  normal record for x.y.dom.  With axfr-get and tinydns(8),
       the records apply to y.dom and anything.y.dom except x.y.dom.

       axfr-get does not precisely simulate BIND’s  handling  of  multiple  IP
       addresses  for  a  single  name.  When there are more than 8 addresses,
       tinydns(8) selects a random set of 8 for each query.


       axfrdns(8),  tinydns(8),  tinydns-data(8),  tcpclient(1),  softlimit(8)