Hello list, This first my message here but I'm the author of the original question :-) I finally succeed in reverse proxying OWA adding the login=PASS option to my cache_peer directive. For future reference, here is the complete line: cache_peer exchange-fe.local.mysite parent 80 0 front-end-https=on \ originserver proxy-only connection-auth=off login=PASS Adding RPC_IN_DATA and RPC_OUT_DATA to the extension_methods gives me rpc over http capability which is definitely great. Many thanks for you help! I'm now trying to reverse proxy a second url (with another backend) on the same box using an IP alias on the squid server. The backend is using https protocol so I setup the following cache_peer for this backend: cache_peer backend.local.mysite parent 443 0 originserver proxy-only connection-auth=off ssl cafile=path_to_ca_of_backend However, the squid -k parse returns: parse_peer: token='cafile=/path_to_ca_of_backend' FATAL: Bungled squid.conf line 559: cache_peer backend.local.mysite parent 443 0 originserver proxy-only connection-auth=off ssl cafile=/path_to_ca_of_backend Squid Cache (Version 2.6.RC2-20060628): Terminated abnormally. Is this cafile= option already implemented on this 2.6RC2 or am I doing something wrong? Many thanks. Best Regards, Benjamin Constant The information contained in this transmission may contain privileged and confidential information. It is intended only for the use of the person(s) named above. If you are not the intended recipient, you are hereby notified that any review, dissemination, distribution or duplication of this communication is strictly prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.