Whenever I open up Outlook, I get a dialog box asking for Microsoft LDAP Directory settings for port 3286.
What do I need to fill in here?
Probably nothing as chances are high that you are not using an LDAP directory as an address book. If you do, you can stop reading this and contact your mail administrator and ask for the settings that you need.
Usually when you get this dialog it means you have just finished upgrading from Outlook 2000 or previous or moved from Outlook Express to Outlook instead. In those cases, it sometimes happens that the LDAP service is left in Outlook after transferring your contacts. If that happens, you can remove it manually.
File-> Account Settings-> Account Settings…-> tab Address Book-> select the Internet Directory Service (LDAP)-> button Remove
Tools-> Account Settings…-> tab Address Book-> select the Internet Directory Service (LDAP)-> button Remove
Outlook 2003 or Outlook 2002/XP
Tools-> E-mail Accounts…-> View or change existing directories or address books-> select the Internet Directory Service (LDAP)-> button Remove
Note: when upgrading Outlook or migrating away from Outlook Express or Windows Mail it is recommended to start of with a clean mail profile instead of upgrading the current one or exporting your account settings.