Subject: barking up the wrong trees
“Failed to connect to SMTP host”, with the message continuing to sit in your mail.box, just means that the recipient’s server was not available/responding when Domino tried to route the message to that server. That can mean that the recipient’s server was down or busy, or that the bandwidth to the internet was busy.
Another thing you need to be aware of is TIMING of mail router delivery. The first wait period is defined in the Configuration Settings document, Router/SMTP - Restrictions and Controls - Transfer Controls tab, “Initial transfer retry interval”. (If you decide to change this, I wouldn’t set it too close together. A server that is busy/down isn’t likely to come back up in, say, 2 minutes. Also, it will create more work for your server continually trying to deliver these messages.) By default, the router will try the message once, and if it fails it will try again at the following intervals: 15 mins, 45 mins, 2.25 hrs, 6.75 hrs, 20.25 hrs. This continues until the timeout is hit. (see below) So, you can see how if there was a problem with the recipient’s server early on, it quickly gets to the point where the message is sitting for a long time without even TRYING to be delivered. When you restart the router, it resets this and tries to send right away. So, if their server was previously unavailable and had recently become available, then it LOOKS like restarting the router solved the problem, when all it did was make the server try to deliver the message. This is explained in the Admin Help document “Setting transfer limits”.
See also the Admin Help document "Setting the message time-out value ". This setting determines when Domino gives up on sending a message and fails it. If you want to get failures sooner than the default, this help doc explains how to change that. This value is worth changing (see the setting at the bottom for “MailTimeoutMinutes”), because it will bounce the delivery failure back to your users sooner.
Our new mail server’s IP address does not appear to be on any blacklists.<
If you were on a blacklist, you would get a delivery failure (to the sender’s inbox) stating that the message was rejected, and possibly giving a reason or RFC code.
Tracert<
Tracert just tells you the route the message WOULD take to get to the server, but it doesn’t tell you if the SMTP service is available on the recipient server, or if it would accept a connection. Also, are you looking at domain.com, or at the primary MX for domain.com ?
Start by using a public MX lookup to find out the mailserver for that domain. (I recommend http://www.zoneedit.com/lookup.html .)
Then, test the SMTP server to see if it will accept a message from you, by starting at a command prompt:
telnet mailserver 25
helo fromaddress
mail from: fromaddress
rcpt to: destinationaddress
data message
period on a line by itself
quit
If it accepts that test message (which will actually be delivered), then it is accepting messages. Your message SHOULD be able to go through AT THIS TIME. - But that doesn’t mean there wasn’t a problem previously, which is the catch. Just because you can connect now, doesn’t mean that Domino should have been able to connect earlier. There may have been a problem earlier.