[Mimedefang] problems processing mails with many attachements

[Dirk Mueller]

Hi, 

I keep receiving a looping bounce on my mimedefang-enabled mail gate which 
has meanwhile about 1200 mail parts. its about 2.5MB in size. 

This causes my mail server to run into 800MB swap (it has 1GB RAM) for about 
5 minutes. there is one mimedefang process hanging processing it with 100% 
CPU and over 70% of the available memory. 

As the mimedefang-filter times out, sendmail rejects the mail with 4xx and 
the mail is coming again 5 minutes later, starting yet another process of 
mimedefang, while even the first one hasn't finished yet. the system load is 
slowly going through the roof :-(

I've tried commenting out all virus and spam checking etc and it still hangs 
and still eats this awful amount of memory. 

is there any way to avoid this denial of service ? can something be done 
about reducing the memory consumption ? Can I simply not decode mails with 
so many attachements ? can I make sendmail reject mails which timeout in the 
milter with a 5xx code so it doesn't come back ? can I do anything?

it basically doesn't seem to do anything but calling filter(). no virus or 
spam checking (which is limited to a certain mailsize). I have no idea what 
it does, but its doing it very slowly, its a dual Athlon MP 1800 so surely 
no slow machine. 

Please, its urgent, I see my mail server slowly dying, because a lot of 
other mail isn't processed in time because it is so busy with this one mail. 


-- 
Dirk (received 305 mails today)