Hi juan_g, hello Till,
First of all thank you very much juan_g for the above posted link http://www.question-defense.com/2009...email-messages
who saved me to retrieve my mails again and specially this part on master.cf:
#amavis unix - - - - 2 smtp
# -o smtp_data_done_timeout=1200
# -o smtp_send_xforward_command=yes
After an update from the 188.8.131.52 Version to 3.0.3 of ISPConfig, Postfix was rejecting every sent mail. As with you, I couldn't use amavis or clamav on my hosted VPS, since its resources are not really sufficient.
And for your suggested combination with GoogleApps, I find the idea not bad. But I think, the idea behind to "administer" an own mailserver is to feel free from any third-party solution, even if some features are missing. Talking about my case, I'm using Postfix for personal purpose, therewith avoiding Freemails & Co. and learning progressively to administer this robust mailserver. And fortunately till now it's still running spam-free