Netmail Archive 5.3 with Exchange 2013
When running a Netmail migration job, some messages fail to inject and fail with the following error: 'message over 64mb, skipping.' This is related to the message size exceeding Exchange server default size limits.
The maximum message size allowed by Netmail in versions prior to v5.3 was 100 MB, however the client-specific maximum size limit for Exchange Web Services clients recommended by Microsoft is 64 MB (default value), as explained in this article.
Based on this, Netmail adjusted the maximum allowed message size to match Microsoft’s recommendations. This article will explain how to allow messages larger than 64 MB to be injected by modifying the maximum message size attribute in eDirectory to override this default value.
The article will also explain how to update the maximum allowed message size configuration on the CAS and mailbox servers.
Although Netmail Archive Injection jobs may allow any size message to be injected, problems may arise with messages that exceed the Microsoft recommended size allowance of 64 MB, and errors of the type 'message over 64mb, skipping' may be associated with messages that exceed the default value.
For this reason, the maximum message size that Netmail Migration jobs will inject (with Exchange 2013 on-premises) is now 64 MB to match Exchange defaults (lowered from 100 MB).
Messages smaller than 64 MB in size will inject successfully, but any exceeding this size limit will fail to inject with the following error:
Time: 2015-01-23 11:17:19 Source: maewsapi Message Id: 54c22ec7.netmail.suppt.100.1746622.214.171.124
Subject: test 73mb
Description: transaction error [add] message size is larger that 64 megs. skipping.
It is, however, possible to change this limit. The default value can be overridden by setting the MaxMessageSizeinMegs maParameter against the Migration job in eDirectory; this attribute allows another message size to be specified.
To set this attribute and specify a value, connect to the eDirectory tree hosting the Netmail objects and navigate to the migration job object, located at: GWOpenNode > Jobs > Migration Agent_<job-name> (refer to the screenshot below).
Edit the maParameters attribute for the job and set the value to the desired size using the following format: <MaxMessageSizeInMegs> xxx</MaxMessageSizeInMegs>; save the changes to allow messages larger than 64 MB to be injected.
The next step is to configure the maximum message size configuration on Exchange CAS and mail servers.
To make sure that the Exchange CAS servers and mail servers are setup to accept a new size limit (if it exceeds 64 MB), the maxAllowedContentLength value in the EWS configuration should be modified in the web.config file in the following two locations:
C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\exchweb\ews (mailbox servers)
C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\ews (CAS servers)
In each of these locations, open the web.config file for editing. Locate the following line, and enter the desired value: <requestLimits maxAllowedContentLength="XXXXXXXX" />
It is important to note that In Microsoft Exchange Server 2013, there are several different message size limits that apply to messages as they travel through an Exchange organization. If the Exchange organization-wide message size limits are changed, it will also be necessary to verify that the message size limits for Outlook Web App, ActiveSync, as well as Exchange Web Services are set accordingly. This Microsoft Exchange 2013 article explains how to configure client-specific message size limit values in the web.config files on CAS and Mailbox servers for Outlook Web App and email clients that use ActiveSync or Exchange Web Services (EWS).
Once all the configuration files are updated with the new size limit, restart IIS on all CAS servers to commit the changes. To do this, open a command prompt and issue the following command on each CAS server: iisreset
If it is important to avoid short disruptions to mail access, run this command after peak hours.