Notes from the Lab

The Mystery of Heuristics

July 17th, 2006

Microsoft would’ve made my job a lot easier if they had documented heuristics attribute. It contains a lot of interesting system information about an Exchange server object for any software that can read from Active Directory. Unfortunately, all the information there is presented in bits and all the documentation… is not presented at all. I take that back. You can find this:

Contains special connector attributes, such as “allow system messages”.

OK, that helps… Also, you can find this:

Bit	Value	Significance
0	0	Replication of attribute between sites
	1	No replication of attribute between sites
1	0	Not accessible by anonymous clients through LDAP
	1	Accessible to both anonymous and authenticated LDAP clients
2	0	Not accessible by authenticated clients through LDAP
	1	Accessible to authenticated clients but not to anonymous clients
3	0	Not an operational attribute
	1	An operational attribute
4	0	Not visible through the Administrator program, on the Attributes tab of the DS Site Configuration object (property page can be used to configure the non-operational attributes of the site)
	1	Visible through the Administrator program, on the Attributes tab of the DS Site Configuration object

Not a lot. Especially, if you remember that the second piece is actually about Exchange 5.5.

During the last several month we also found a couple of things about heuristics information:

• Bit 11 (2048) is set to 1 if the Exchange server is a cluster EVS.
• Bit 29 (536870912) is set to 1 if RPC over HTTPS is enabled. This one is a courtesy of Bharat.

That’s it. If you know anything else on the topic, feel free to contact me.

Entry Filed under: Exchange