fetchmail -> sendmail problem

[Karsten Fuhrmann]

Hello,
i have a problem with some strange spam emails, which lock up my  
email reception.
The problem is the following : I am using fetchmail to download my  
email (from a pop3 server), and fetchmail passes the email to my  
local sendmail daemon who gives it to my local imap server (cyrus).  
This works fine. But sometimes i got a spam email, which has an  
unresolveable dns origin, and this makes my sendmail crazy in a way,  
that sendmail wants to resolve but gets a timeout (around 20s). In  
the meantime the fetchmail which is actualy waiting for sendmail to  
accept the message gets a timeout from the pop server where it is  
connected to.
Because of that timeout fetchmail stops receiving email from pop  
server and tries again next time, but next time it will start with  
the same spam email again, and it all starts again, actually no more  
new mails will arrive until i delete this particular email from the  
pop server manually.

Is there a way to tweak the timeout behavior of sendmail, or maybe  
even no dns resolve option for sendmail, or even better some way to  
tell fetchmail to use the idle command to keep the connectio to the  
pop server open ?


Greetings,
Karsten Fuhrmann

Cartoon-Film Thilo Rothkirch
System Administration
phone:  +49 30 698084-109
fax: +49 30 698084-29
email: karsten_fuhrmann at web.de