Hi, >> I have a fedora15 installation with postfix-2.8.7 and would like to >> throttle the message rate for incoming mail from senders like >> constantcontact and other bulk senders. I've read about greylisting, >> but I'm not sure what's what I'm looking for, due to the inherent >> side-effects. > > The cleanest way to do this is with firewall rules that limit the > number of connections from a specific host or limit the bandwidth > allotted to them.
Is there not a way to limit the number of messages sent per connection? I believe there are very few connections from these servers, just many new messages for each connections. > Anything you do in postfix is likely to severely delay incoming mail. > > If this is legit mail, what's wrong with accepting it as fast as > possible? If your server can't stand the load you should reduce > default_process_limit to something your server can handle. I tried limiting the default_process_limit in the past, but this of course produces "connection refused" to other clients, which immediately resulted in phone calls from users about our mail server being down. I had previously done something like this with iptables, but it was mostly ineffective: iptables -I INPUT -p tcp --dport 25 -i eth0 -m state --state NEW -m recent --set iptables -I INPUT -p tcp --dport 25 -i eth0 -m state --state NEW -m recent --update --seconds 20 --hitcount 5 -j DROP Thanks for any ideas, Alex
