I have Exchange 2010 running in Windows 2011 Small Business Server.
We recently changed Internet providers and found that some of our outgoing email messages were stuck in the queue with "451 4.4.0 Primary target IP address responded with: ""421 4.2.1 Unable to connect. Apparently, the recipients were blocking our new IP because it was on a dynamic IP list.
The primary concern is that these messages were delayed in the queue and not being delivered to the recipients and it was many hours before we knew there was a problem. Apparently the default retry expiration time out interval is two days. I have found the following to change the default time, but it only speaks of changing the number of days. I was more inclined to change it to 4 hours. That way I'd know if there was a delivery problem a whole lot more quickly. Is there a way to do this or another way to be notified if messages are stuck in the queue?
Configure the message expiration time-out interval
You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "Hub Transport server" and "Edge Transport server" entries in the Transport Permissions topic.
The message expiration time-out interval specifies the maximum length of time that an Edge Transport server or a Hub Transport server tries to deliver a failed message. If the message can't be successfully delivered before the message expiration time-out interval has passed, a non-delivery report (NDR) that contains the original message or the message headers is delivered to the sender, and the original message is removed from the queue.
By default, the message expiration time-out interval is 2 days.
Use the EMC to configure the message expiration time-out interval
1.Perform one of the following steps:
•On a computer that has the Edge Transport server role installed, in the console tree, select Edge Transport, and then click the Properties link that's directly under the server name.
•On a computer that has the Hub Transport server role installed, in the console tree, expand Server Configuration, and then select Hub Transport. In the result pane, select a server. In the action pane, click the Properties link that's directly under the server name.
2.Click the Limits tab.
3.Enter a value in days next to Maximum time since submission (days). In the EMC, the valid input range is from 1 day through 90 days.
4.Click Apply to save your changes and remain in the Properties page, or click OK to save your changes and exit the Properties page.