Hi Raj, I have created a seperat publishing rule for RPC over HTTPS and added /rpc/* to path. I removed other paths: /exchange/*, /exchweb/*, /public/*. It is interesting to know for me: I used the same listener in RPC over HTTPS publishing like in OWA publishing. It menas that the Listener has the authentication Forma-based authentication. But I tried both form-based and standard authentication for RPC over HTTPS. It didn't help me. To your previous mail: I didn't have the record of EXchange back-end server in the external DNS. THat is also not my wish. I want o protect back-end from hackers. Because of that I have twio Firewalls and ISA 2004 in Lab. Only ISA external IP address should be connected by extern clients. THen, you know, ISA will forwar (SSL bridging) traffic to front-end. I tested your suggestion before. If I have the back-end in the DNS list and type back-end Exchange in Exchange Server field, I can connect me over RPC over HTTPS. Best Regrads Mustafa