Hi,
I´m glad that I just finished my " toaster" today, but as I just put it online and a strange problem started: I couldnt sent e-mails. Pstree shows that the maximum number of qmail-smtpd are active, and telnet´ing to port 25 didnt work. Soon, I realize that someone was trying to send a large amount of spam to my server (chkuser patch works very well btw...), and to do that the evil spammer opened all the connections that he could until the tcpserver hit the concurrencyinconming connections.
The incident make me thinking about a way to handle this kind of problem, and seems to me that if I could limit the number of connections from a single IP my server would not suffer this kind of DOS again.
Tcpserver doesnt have this kind of control, right? it can only limit the maximum number of connections, no matter from where they come. It there a way to do that?
tcpserver does not have support for limiting the number of connections per IP. You can use courier-imap's pop3d server with vpopmail, as couriertcpd DOES support this.
Regards,
Bill Shupp
