I'm getting (delivery temporarily suspended: SASL authentication failed; server myserver.com[xxx.xxx.xxx.x] said: 535 5.7.3 Authentication unsuccessful) when I try to relay mail from Postfix 2.5.5-1.1 on Debian Lenny box to Exchange 2010. I think I tried all possible combinations but I'm definitely missing something. Here is relevant part of main.cf: broken_sasl_auth_clients = yes smtp_sasl_auth_enable = yes smtp_sasl_security_options = noanonymous smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd smtp_pix_workarounds = smtp_sasl_type = cyrus smtp_always_send_ehlo = yes relayhost = myserver.com And I got libsasl2-modules installed. Anybody managed to successfully relay mail between Postfix and Exchange? Oh, and I already double-checked if password is right.