I want to make a connection between an external LDAP server (e.g. Active Directory server) and my webservice. I want to make sure that a certain group of users from the LDAP server stays in sync with my webservice, e.g. when a user gets deleted from the LDAP server, the LDAP server should push this change to my webservice so the user can be deleted from my webservice as well.
Any suggestions on how to achieve this?
The comments to your question indicate that you should retrieve data as required from the directory server instead of trying to maintain synchronization, with which I agree.
If synchronization is still your desire, you may be able to use persistent search, which notifies the connected client of changes in the database according to search parameters. Not all server support this mechanism, however.
see also