On our Zimbra 6.0.5 server running on Fedora 6, it seems that all messages are being tagged by spamassassin with NO_DNS_FOR_FROM (despite having legitimate sent addresses). How should I debug this? ...
Symptoms : our mail server, a dedicated Fedora server with zimbra, stopped working, in such a way we couldn't even log in with SSH. Soft reboots, through our web admin console, did make it work again, ...