Recommended interval to Configure the message expiration time-out interval in Exchange 2010

Hello experts!
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.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Simon Butler (Sembee)ConsultantCommented:
I wouldn't recommend reducing the expired time to 4 hours. That is a very short time. Most sites expect people to be trying for two days which gives them time to resolve issues.

Your problem here is actually with the recipient. If they had found your IP address on a blacklist then they should have NDR'd the email back with a permanent failure. You would have got the message back immediately and could have resolved it. They were sending back a temporary failure. Without looking in the queue you wouldn't see the true message, as it would simply time out.

Otherwise, monitor the length of the queue. Loads of applications can do that, you can even get PowerShell scripts which will send you an email if the queue is above a certain length of time.
For example:
(It does require some modification for Exchange 2013, but easily done if you look at the script).

baggio8Author Commented:
I'm very pleased to see your response as I have seen your expert advice for many years and know that I am in great hands.  
Agreed, the sender should just outright reject the connection with an NDR.  I have to take responsibility for this because there are time sensitive contacts that are being made to our clients and if there is a long delay we are not servicing our customers in a timely fashion.
I think this script is going on the right track, but if I understand it correctly, it is based on the number of messages in the queue rather than the length of time it is in the queue.  Is there a script that will message me if there is an email in the queue exceeding 2 hours?  Also, we noticed that eventually after several hours some senders were notified that there message was delayed:
Delivery is delayed to these recipients or groups:
Subject: RE: Testing Item19-r - Roll Cur2Std
This message hasn't been delivered yet. Delivery will continue to be attempted.
The server will keep trying to deliver this message for the next 1 days, 19 hours and 54 minutes. You'll be notified if the message can't be delivered by that time.
Can this delay message be consistently sent to the sender after 2 hours?

Simon Butler (Sembee)ConsultantCommented:
You can change the notification time down - that isn't uncommon to do.
EMC, Server Config, Hub Transport. Right click on the server and choose the Limits tab. Restart Transport afterwards.

As for a script to alert on time in the queue - I haven't seen one myself and have looked around quickly to see if someone had written one. Alerting on items in the queues over two or three should catch most things though because items wouldn't normally stay in the queue at all.


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
baggio8Author Commented:
Changing the notification time is a good option.  I set it to 1 hour.  That way I can investigate any delays promptly.  Thanks for your work.

It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.