Prior to V8.10 sendmail, redirecting email with a ph server required running the phquery program. Beginning with V8.10 sendmail, a new database class called ph has been added that allows sendmail to perform direct ph queries. The use of ph maps is described in ph. To enable such maps, you can add a line such as the following to your Build m4 file:

APPENDDEF(`confMAPDEF', `-DPH_MAP')

If you are running a precompiled sendmail binary, you can use the -d0.10 debugging command-line switch (-d0.10) to determine if PH_MAP support is defined (if it appears in the list, it is defined).