Document information

Document ID: 4670
Subject: Maximum Email Size
Creation date: 12/14/15 4:35 PM
Last modified on: 4/12/22 11:54 AM

Configuring maximum email size

By default, Xeams rejects messages larger than 20MB. This is done by design and it is configurable. However, before you change this behavior it is important you understand the implications this can have on Xeams.

Email servers are not designed to handle large attachments and neither is Xeams. This is because large messages require more memory for processing. This memory requirement affects Xeams more than other email servers that do not analyze incoming messages.

Additionally, Xeams uses a multi-threaded architecture to process incoming messages. This means messages containing large attachments can come in from different sources simultaneously adding up to a large memory usage.


A better solution is to use a product that is designed for large attachments. One such product is SynaMan, which can handle emails containing gigabytes of attached files. It is an easy to use, feature rich, file sharing tool designed for large attachments with an embedded SMTP server. You can use both Xeams and SynaMan in conjunction to employ Xeams' powerful Spam filtering and SynaMan's large file capabilities.

Modifying configuration in Xeams

Use the following steps to modify the maximum email size in Xeams:
  • Hover your mouse over Filter Management and click on Message Size
  • Modify the Maximum "Global" size field. We strongly recommend not using a number higher than 30 MB, as that can potentially bring down the entire server

Usage Tip

Email size is usually 30% larger than the attached file. This happens because attached files get encoded in to BASE64 format, that increases the size of an email by about 30%. Therefore, if you specify 30MB in Xeams you will only be able to attach files that are 25MB or smaller.

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