Email attachment limitations with TZO Outbound Mail Relay (OMR)

20 megabytes is the maximum size of an email 'message body' which can be sent through the TZO OMR service. The practical real world 'file size' tends to range from 16 to 18MB.

NOTE: For reasons beyond the scope of this FAQ, it should be noted that ALL file attachments will have 'overhead' due to the encoding process. Some files will require more overhead than others. Therefore a file that seems to be under the 'limit' could actually exceed the limit once attached and encoded.

Limitations and Support Issues

If your outbound SMTP server does not use TZO OMR, then none of the above applies. OMR is an optional service offered by TZO.

Email is not an efficient method for transferring large volumes of data on a routine basis, and OMR cannot substitute for a FTP or webserver. Please investigate these methods of file transfer if large volume transfer is needed

Additional limitations may be imposed by your email server's configuration. For example, your mailserver or antivirus may object/block your outbound email before it even reaches the OMR server.

If your email does not exit your local queue, check your mailserver logs (or turn up logging). Note that the TZO OMR server will always provide a meaningful SMTP error if there is a problem.

There is no guarantee that a destination target mail server will accept attachments (at all, or over a certain size such as 10MB).

There is no guarantee that a destination target mail server will accept attachments at all.