[ActiveDir] Single Space in LDAP query dropped: Why?

[Jef Kazimer]

I had posted this today, and I was curious if anyone knew why an LDAP filter drops the query when searching for a single space value?  Though I was using Joe's ADfind, I did have the same results in ADSIedit, and thought someone better than I, may know why.  It's not really a problem, just a curiousity.   Thanks,   Jef     http://jeftek.spaces.live.com/blog/cns!F2042DC08607EF2!642.entry   LDAP queries are spaced out... I was looking at a metaverse object in MIIS today noticed some admin had set the mail attribute to a single SPACE ( ) character.  The Metaverse is stored in a SQL server, so naturally the query structure is different than any constraints of LDAP. I wanted to discover how many other user objects had the same issue, so I decided to pull out ADfind and issue this command: ADFIND -H MYSERVER -DEFAULT -F "(&(objectCategory=person)(mail= ))" -C 0 found ok, so I thought it was my lack of quoting and tried: ADFIND -H MYSERVER -DEFAULT -F "(&(objectCategory=person)(mail=' '))" -C 0 found Since it's command line I was sure that the quoting would encapsulate it correctly, so I figure it is being stripped out by the LDAP query (I made this same Query ins ADSIedit and LDP with no luck) so perhaps there is an escape character for such a thing.   I have done many queries with filters like "description=The Man", and the space was interpreted correctly.  Yet it seems, a single space, by itself is not passed to the query correctly. So I check out the uber friendly RFCs and find escape characters for types such as * and NUL, but really no mention of  a single space as anything special.  I checked the LDAP V3 RFC as well for any real mention of when and when a single space is dropped from the query, finding nothing related. Fortunately,  using the escaped sequence in the query ("mail=\20") to represent a space worked just fine and returned the object I was looking for. ADFIND -H MYSERVER -DEFAULT -F "(&(objectCategory=person)(mail=\20))" -C 48 found So LDAP filters can container spaces as the value being queried for, but cannot be a single space without using an escape sequence to represent the value. I suppose it's kind of silly, but I had never really looked for such an occurrence before, so it was an interesting learning experience.