The Null backend to slapd(8) is surely the most useful part of slapd:
- Searches return success but no entries.
- Compares return compareFalse.
- Updates return success (unless readonly is on) but do nothing.
- Binds other than as the rootdn fail unless the database option "bind on" is given.
- The slapadd(8) and slapcat(8) tools are equally exciting.
Inspired by the /dev/null device.