>trojaned computers usually don't wait for HELO or ok. They just start >sending data. So having a delay of 2-5 seconds before the HELO answer >helps you identify the spam sending hosts. I think it's a standard >option in exim, sendmail etc. >not effective as graylisting, but a good antispam measure anyway
really? Adding a 5 sec delay to SMTP greeting would almost double the avg session length. Kerio e.g. thinks that 25 to 30 seconds is optimal (Shorter delay might not be enough (the spam sending applications use 10-20 sec), longer time would impede the communication. So we have many many more open connections at any given time. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Assp-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/assp-user
