09.04.03

[Exim] SMTP protocol violation: synchronization error

Posted in internet at 9:13 am by James

This has to be one very annoying message introduced to minimize spam attacks or other hacks. This check (in accordance with the SMTP protocol) was added in exim4. A paper on the exploits is available at:

http://www.remote.org/jochen/sec/hfpa/hfpa.pdf

It turns out that my firewall was also causing problems since i disabled ident. Mailers send back and ident to verify the sender!