Recently there have been many viruses going around that generate emails to recipients not in our domino directory. Our server rejects these messages, but this is done one-by-one and the sending server is trying to send the message to dozens of bad recipient names.
I log these and have accumulated 100,000 bad names in the last 10 days. Its difficult to determine the sending IP address from the server log, but I think it is from ISPs like Verizon. Infected p/cs no doubt.
Is there any way to tell the smtp server to break the connection on the 2nd bad recipient?
Subject: Can SMTP break connection when recipients not in domino directory
In the server configuration setting document, tab Router/SMTP, subtab Restrictions and Controls, subtab SMTP Inbound control, there is a setting Verify that local domain recipients exist in the Domino DirectoryIf you set this to enabled, the domino server generates the smtp error: 550 bad_user@yourdomain.com … No such user after a RCPT TO: command with a bad name. That means, the mail transfer is interupted before the mail data is send. So there is no dead mail in mail.box.
Thats the best you can get.
The domino server won’t break a connection completly in respond to a false address, I think, that would be a violation of the RFCs governing SMTP behaviour.
Subject: RE: Can SMTP break connection when recipients not in domino directory
I agree with Andreas that this is a way to conserve bandwidth and reduce the strain on your server. I recently had smtp debugging enabled and was surprised at the number of errors some of these senders were generating. In spite of my server saying over and over that the sender was committing multiple smtp errors some of these guys won’t take no for an answer. I solved this with “smtperrorlimit=2” in the ini, which drops the connection when the sender exceeds that error count.
Subject: RE: Can SMTP break connection when recipients not in domino directory
Wow, you guys are great! I put SMTPErrorLimit=2 in the .ini file, bounced SMTP and over 10 minutes 6 servers have connected, got 2 ‘recipient not found in the Domino Directory’ and then disconnected right after the second recipient message. This should really reduce the SMTP load when these virus’s get so widespread as they are now.
Subject: RE: Can SMTP break connection when recipients not in domino directory
Will this work on Domino 5.012–Setting SMTPErrorLimit=2 ? I’ve been having a similar problem and am upgrading to 6.5.4 in a month but would like to do something about all the junk mail in the meantime. It’s increased dramatically in the last couple of weeks.