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 picture for a 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.

For more than 20 years, David Gewirtz, the author of Where Have All The Emails Gone? and The Flexible Enterprise, has analyzed current, historical, and emerging issues relating to technology, competitiveness, and policy. David is the Editor-in-Chief of the ZATZ magazines, is the Cyberterrorism Advisor for the International Association for Counterterrorism and Security Professionals, and is a member of the instructional faculty at the University of California, Berkeley extension. He can be reached at david@zatz.com.