By David Gewirtz
We've gotten this question a few times from readers in the past month. They've installed Domino on a Windows server, and while the Domino server itself works, they're getting a strange error about LDAP (Lightweight Directory Access Protocol) not working. The specific wording of the error is:
LDAP server: listener failure, TCP/IP port number (389) is already in use on this system.
What makes things interesting is that, for some folks, no amount of searching on the Windows server, in the Services, or elsewhere will show LDAP running. So, what's happening?
It turns out that this is an artifact of running Active Directory on the server, usually if Domino is running on a Windows 2000 or Windows 2003 Domain Controller. Active Directory uses LDAP internally, and insists on using port 389.
Fixing this is easy, although it does force you to change the LDAP port Domino uses. We haven't seen any problems after making the port change, but if any of you know of any cascading side effects of changing the Domino LDAP port, please send a note to me at david@ZATZ.com.
To change your LDAP port in Domino, hit your Configuration tab and select Current Server Document. On the server document, hit the Ports tab and then the Internet Ports tab, as shown in Figure A.
FIGURE A
Navigate to your LDAP port settings. (click for larger image)
There's one more tab to hit, the Directory tab lower down on the page. Then, all you need to do is change the port in the TCP/IP port number field. Again, be sure you're on the Directory (LDAP) tab. Although it's often difficult to pick a free port number, you could do a firewall port scan, or (what we'd do), pick a port number somewhere above 10,000.
Restart your Domino server and the error will go away. We've only heard about this problem for Domino 6+ servers, but if you've experienced (and fixed) the problem in earlier servers, please let me know.