NAME

      walldns  - a reverse DNS wall server

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.  IPv6 addresses are treated similarly, but now
       using ip6.arpa as reverse IPv6 address suffix.

CONFIGURATION

       Normally walldns is set up by the walldns-conf 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.  Specifying 0.0.0.0 or :: results
       in listing to all available IP addresses and interfaces (for IPv6)
       respectively.  In case $IP is specified as the pseudo IP address :0
       walldns will bind to all available IPv4 and IPv6 addresses
       simultaneously.

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)

REFERENCE

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