> It's a war of attrition. There's not much that can be done except to keep
> scaling up the system to cope with the load. It's not only SMTP, for > example. DNS server operators, for example, often have no choice but > overprovision their bandwidth and CPU to deal with attacks on DNS servers. hmmm ... I would think that if the SMTP connection is handled by a program which does not create a process or thread for each handshake before it has done a DNS RBL check it would increase the systems resistance to spam waves dramatically. I mean something like lighttpd which works as a single process with a single thread and non-blocking I/O. Instead of select, he used the fastest event handler in the target system: poll, epoll, kqueue, or /dev/poll. He chose zero-copy system calls like sendfile rather than read and write. take a look at: http://www.kegel.com/c10k.html I like courier, it worked for years for me. It is one system for all you need on a mail server. But it's architecture is vulnerable to spam waves. I don't want to replace courier with something else, so I send my first mail with the search for: - some tuning tips I can use - I've posted the ones I'm using, but maybe there are others. the dns rbl check fails but the connection is kept open. Can courier not just drop it? - possibility to use a proxy which has the above described features and only lets stuff though which passes the dns rbl checks. - or anything else I can do with the exception of replacing the hardware or courier itself. > But it's really not a problem unless you're maxed out on connections for a > prolonged period of time. SMTP is not instant messaging. If the sender > cannot connect, the sender will try again later, so if this goes away > before > long, you won't really have any long term impact. true, but my monitoring gets wind of it, send sends me an alert - and monitoring I do need. ;-) -- Regards, Robert ----- Robert Penz ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ courier-users mailing list [email protected] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
