walldns 8
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