NAME

       walldns - a reverse DNS wall

DESCRIPTION

       walldns  is a reverse DNS wall.  It accepts iterative DNS queries for in-addr.arpa domains
       from hosts around the Internet, and supplies generic responses that avoid revealing  local
       host information.

       For  example,  walldns  provides a PTR record for 4.3.2.1.in-addr.arpa showing 4.3.2.1.in-
       addr.arpa as the name of IP address 1.2.3.4, and a matching A record  showing  1.2.3.4  as
       the IP address of 4.3.2.1.in-addr.arpa.

Configuration

       Normally walldns is set up by the walldns-conf(8) program.

       walldns  runs chrooted in the directory specified by the $ROOT environment variable, under
       the uid and gid specified by the $UID and $GID environment variables.

       walldns listens for incoming UDP packets addressed to port 53 of $IP.  It does not  listen
       for TCP queries.

Further details

       walldns  rejects  inverse  queries, non-Internet-class queries, truncated packets, packets
       that contain anything other than a  single  question,  queries  for  domains  outside  in-
       addr.arpa, and request types other than A, PTR, and *.

       walldns does not include NS or SOA records with its responses.

       walldns uses TTLs slightly over one week.

SEE ALSO

       walldns-conf(8)

       http://cr.yp.to/djbdns.html

                                                                                       walldns(8)