Thanks for all ur past replies........ I am a beginner in openLDAP field.....I am just started get familiarize with openLDAP features... Curently I am working on to test LDAP sync feature. My openLDAP server is running on suselinux machine and I have written a test code that acts as a client , trying to bind with the server. Slapd.conf , ldif file all have been configured and I am able to perform add , delete and other operations. I want the clients to be notified about the changes that have happened in the server...... My objective initially is a single server multiple client communication...... As I mentioned earlier I am using ldap sync APIs , first initialised the sync structure by calling ldap_sync_initialize and then calling ldap_sync_int after getting a suucessful connection and binding it to the server , and other necessary structure fields are also assigned respectively..... But "Unavilable critical extension is thrown" The solution given was to use slapd as a provider and use slapo-syncprov..... so my ldap server is the slapd provider but there are no consumers here....... slapd.conf is modified to include syncprov overlays in the server side ...but I dont know what more to be done in the client side.........The error was not been able to resolve.... I was not able to get information required by me from any where........ I wanted to use only LDAP content synchronisation protocol.........sync repl is not considered now.... It will be so thankful if u can provide me some guidelines in this aspect......... Irfaz Sait Software Engineer Huawei Technologies India Pvt. Ltd. INNOVATION NEVER STOPS! This e-mail and attachments contain confidential information from HUAWEI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient's) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!