Dirsync: Is it possible to match on employeeID attribute?
This is not directly possible.The available matching attributes are as follows, choose at least 1 with a maximum of 3:
userPrincipalName
mail
extensionAttribute1-15
As a workaround test syncing the employeeID to one of the extensionAttribute1-15 and use this.
Select a pair of attributes which will match exact values from the source user object to the target user object to discover and match the appropriate user accounts.