Process messages that cannot be sent on the Exchange Server

In the Exchange environment, information cannot be sent for many reasons. For example, a communication line may fail, or the domain name Parser (DNS) may have a problem and cannot resolve the receiving domain. In either case, messages that cannot be sent may cause a breakdown of communication traffic among your employees, suppliers, and customers. Fortunately, you do have some means to control how Exchange handles messages that cannot be sent.

Option for accessing unsent Information

In Exchange Server 2003, the option of not sending information is under the control of the virtual Server level at the SMTP level. To access the options that cannot be sent:

1. open the Exchange System Manager and go to the Management Group through the console tree structure, and then go to your management group ", click "server"> "your server"> "protocol"> "SMTP"> "Default SMTP virtual server ".

2. Right-click "Default SMTP virtual server" and select "properties ".

3. Click the "send" tab to view options for unsent messages.

As the default value, if the Exchange server cannot send messages, it will retry in 10 minutes. If Exchange still cannot send messages, it will wait 10 minutes before the next attempt to send messages. If the message cannot be sent at this time, Exchange will retry for the third time.

If the message is still not sent, Exchange will try to send the message every 15 minutes in the next two days. If two days have passed and Exchange still cannot send the information, an unsent Report will be generated.

In Exchange Server 2003 SP1, the Windows operating system sets the bad mail directory to disabled. However, in earlier versions of Exchange, a copy of information will still be placed in the BADMAIL directory. There is no limit on the capacity of this information in the BADMAIL directory until a large amount of unsent information is placed in the BADMAIL directory, making the disk space of the server insufficient.

Modify option of mail not sent

Now that you know how Exchange processes unsent information, let's take a look at how you can modify the process of Exchange. As you can see in Figure A, in the default SMTP virtual server attribute, the sending tag allows you to retry for the first, second, and third times. You can also control the expiration time of these messages.

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Another aspect worth mentioning in the value of this label is the Delay Notification setting. As the default value, Exchange is set in this way. If the message cannot be sent within 12 hours, the sender will receive a message prompting that the message has not been sent, however, there is no need to resend it. You can change the notification time from 12 hours to any time that suits your needs.

Set BADMAIL options

As I mentioned earlier, in earlier versions of Exchange, the BADMAIL directory played a black hole role for unsent information. I think it is wise to disable the BADMAIL directory in Windows, because most administrators never use the BADMAIL directory. But if you do need it, you can enable the BADMAIL directory by modifying the registry and prevent it from increasing to an unreasonable size.

Before I show you how to set the BADMAIL option, remember that it is dangerous to modify the registry. Once you make a mistake, it may destroy your Windows operating system and your applications. Therefore, before proceeding to the following operations, back up the entire system.

Next, you can access the BADMAIL settings in the key value HKEY_LOCAL_MACHINE \ System \ Current Control Set \ Services \ SMTPSVC \ Queuing.

Once there are two different registry key values, you should pay attention to the following (if they do not exist, you need to create these key values ):

1. The first key value is the DWORD Value named MaxBadMailFolderSize.

This key value indicates the size of KB that can be added to the BADMAIL folder before the old project is discarded. In Exchange Server 2003 SP1, The BADMAIL folder is disabled, so the default value is 0. If you want to restore the BADMAIL folder to the running mode before SP1 and allow unlimited growth, change the value to-1. Otherwise, only the folder size is defined. For example, if the value is 3072, the size of the BADMAIL folder can be increased to 3 MB.

2. Another key value that needs your attention is the DWORD Value named BadMailSyncPeriod.

This value tells Exchange how long it will take to check the size change of the BADMAIL folder. If you manually delete some projects in the BADMAIL folder, Exchange will not immediately find that these projects do not exist until it runs the synchronization program of BADMAIL. This value tells Exchange how long it takes to run a synchronization program.

If the synchronization cycle is set to 0, it means that the synchronization is disabled. However, if you want to, you can set it to-1, which allows Exchange to run as before SP1. You can also set the interval of running the synchronization program to several minutes. If you choose to use the BADMAIL folder, we recommend that you run the BADMAIL synchronization program every 10-15 minutes.