The Sikh Geek

Sometimes you learn from your mistakes and this was one of them. I had configured the SMTP service on Windows Server 2003 to send mail out from a MOSS 2007 deployment via 1and1’s SMTP servers (using authenticated access). A few days ago I received an email from them that this account had been sending out a lot of Spam and that the account was being temporarily blocked. After investigating this, I realised that the SMTP service had been configured by me to be an Open Relay! Doh! The mail queue folder had over 80,000 messages waiting for delivery with something like 800MB worth of Spam. I then configured it to only accept connections from the IP address of the MOSS Server and only to relay for this IP address. I then had to clear out the Mail Queue by deleting all the Spam messages in there as well. I had only recently set up the SMTP service and just goes to show you how quickly an Open Relay SMTP Server will be used by Spammers given the chance. I also changed the SMTP service to route via DNS rather than forward through 1and1’s SMTP Server. You live and learn!