Greetings, To run sendmail with the name server you must: 1) rebuild sendmail with the -lresolv 2) rewrite the configuration files The -lresolv selects the gethostby* calls that utilize the name server and resolver. The module that uses the gethostby* calls is daemon.c. An example Makefile is src/Makefile.ns. The directory nscf contains example configuration files for interfacing with the name server. A new right hand side syntax has been added - $[ and $]. Anything enclosed between the two is passed to maphostname in daemon.c to be resolved by the name server via the gethostbyname(). For example the ruleset: R$+<@$-.ARPA> $@$1<@$[$2.ARPA$]> when passed user@host.ARPA will pass host.ARPA to the name server for qualification. This might return host.berkeley.edu if this were host@ARPA's fully qualified name. For additional information about the name server and resolver see the man pages.