Hello, what would be the correct DN for a compare on rootDSE? Although the examples of the manual page seem to be quite specific, none of the following seem to be correct:

:~> ldapcompare -x -Z -H ldap://localhost:9004 "" supportedControl:1.3.6.1.4.1.42.2.27.8.5.1 Compare Result: Inappropriate matching (18) Additional info: inappropriate matching request UNDEFINED

^^^ This is correct; the error results because supportedControl does not have an equality matching rule. I think you can safely work this around by using

ldapsearch -x -Z -H ldap://localhost:9004 -b "" -s base '(supportedControl:objectIdentifierMatch:=1.3.6.1.4.1.42.2.27.8.5.1)' 1.1

If the search returns the rootDSE entry, then you got a match.

p.