Configuring and Managing MPE/iX Internet Services (MPE/iX 6.0)

Appendix C 171
BIND 8.1 Enhanced Features
BIND 8 Highlights
because previous versions of BIND allowed multiple
CNAME records, and these records have been used for
load balancing by a number of sites.
notify If yes (the default), DNS NOTIFY messages are sent
when a zone the server is authoritative for changes.
The use of NOTIFY speeds convergence between the
master and its slaves. Slave servers that receive a
NOTIFY message and understand it, will contact the
master server for the zone and see if they need to do a
zone transfer, and if they do, they will initiate it
immediately. The notify option may also be specified in
the zone statement, in which case it overrides the
options notify statement.
recursion If yes, and a DNS query requests recursion, then the
server will attempt to do all the work required to
answer the query. If recursion is not on, the server will
return a referral to the client if it doesn’t know the
answer. The default is yes. See also fetch-glue.
Forwarding The forwarding facility can be used to create a large sitewide cache on a
few servers, reducing traffic over links to external nameservers. It can
also be used to allow queries by servers that do not have direct access to
the Internet, but wish to look up exterior names anyway. Forwarding
occurs only on those queries for which the server is not authoritative
and does not have the answer in its cache.
forward This option is only meaningful if the forwarders list is
not empty. A value of first, the default, causes the
server to query the forwarders first, and if that doesn’t
answer the question the server will then look for the
answer itself. If only is specified, the server will only
query the forwarders.
forwarders Specifies the IP addresses to be used for forwarding.
The default is the empty list (no forwarding).
Future versions of BIND 8 will provide a more powerful forwarding
system. The syntax described above will continue to be supported.
Name Checking The server can check domain names based upon their expected client
contexts. For example, a domain name used as a hostname can be
checked for compliance with the RFCs defining valid hostnames.
Three checking methods are available:
ignore No checking is done.
warn Names are checked against their expected client
contexts. Invalid names are logged, but processing
continues normally.