Exchange server send/receive limits
Had this question the other day, what are current Exchange on premises limits for messages? And can end users send 10GB file attachments? This site talks about limits, but it also depends on what is available vs. what you can support. By running some PowerShell code, the answers can be provided:
Get-ReceiveConnector | Set-ReceiveConnector -MaxMessageSize 3gb -WhatIf
Cannot bind parameter 'MaxMessageSize' to the target.
Exception setting "MaxMessageSize": "The property, (3 GB(3,221,225,472 bytes)), is out of range. The valid range is from 64 KB
(65,536 bytes) to 2 GB (2,147,483,647 bytes)." + CategoryInfo : WriteError: (:) [Set-ReceiveConnector], ParameterBindingException
+ FullyQualifiedErrorId : ParameterBindingFailed,Microsoft.Exchange.Management.SystemConfigurationTasks.SetReceiveConnector
Get-SendConnector | Set-SendConnector -MaxMessageSize 3tb -WhatIf
Cannot bind parameter 'MaxMessageSize' to the target. Exception setting "MaxMessageSize": "The property, (3 TB(3,298,534,883,328 bytes)), is out of range. The valid range is from 0 B (0 bytes) to 2 TB (2,199,023,254,528 bytes)."
+ CategoryInfo : WriteError: (:) [Set-SendConnector], ParameterBindingException
+ FullyQualifiedErrorId : ParameterBindingFailed,Microsoft.Exchange.Management.SystemConfigurationTasks.SetSendConnector
The server will allow you to send a 10gb message, but it will not allow you to receive it. It is interesting that the send connector goes up to 2TB but the receive stops at 2GB, which seems like a mismatch of configuration options.
This test illustrates another point, even if you did set the send connector to 10GB, the question would be if the recipient would accept it as well as if any other devices in the mail flow process. If someone was trying to send internal only content it would fail due to the valid receive connector limit, if they are sending externally it would depend on the limits of any outbound mail relay devices as well as the recipient mail gateways.
In questions of max send/receive size, the defaults are in the Exchange Online limits as a “best practices” guide. (Also see: Office 365 now supports larger email messages—up to 150 MB)
Furthermore, it would be recommended against a 10gb send/receive threshold due to the current mailbox capacity limits. The default user mailbox size in Exchange Online is 50gb/100gb (depending on licensing), which would mean 5 or 10 emails of that size would hit the mailbox capacity limit. Let’s not even think about what that would do to the database sizing on-premises, especially if the email/attachment was sent to multiple people or forwarded. The math: 100 mailboxes on a database all receiving a 10GB email is ~1TB. That’s a lot of disk space that you must plan for on premises. But hey, aren’t disks free?
Short version: Email is not for file storage/sharing. Best practice in this case would be to use a file share and link to the file or to use a OneDrive share link if the attachments are that large.