I am using exchange 2013 and I have users that when they send any emails with attachments over 20mb, it fails.

How do I change the setting to allow up to 30mb attachments in size?  I've googled this, but to no avail.

In ECP, I looked under mailflow and then rules, but I don't have any rules there. I tried creating one, but I can't because I don't have the enterprise CALs I guess is what it's telling me.

Any help would be apprec

You might want to consider using transport rules to managing Message Size Limits. Hope you may have already referred : Message size limits - https://technet.microsoft.com/en-us/library/bb124345(v=exchg.150).aspx

Hi ,

please have a look in to the below mentioned steps .

1.Please set the max send and receive size on the transport config as 30 MB by using the below mentioned command.

Set-TransportConfig -MaxSendSize "30 MB" -MaxReceiveSize "30 MB"

2.Then set the same size for the mailbox from which you want to send an email with 30 MB size.

Set-Mailbox -Identity "nithya@abc.com" -MaxSendSize "30 MB" -MaxReceiveSize "30 MB"

3.Then the second step would be to set the size for the send and receive connector by using the below mentioned command.

Send connector : 

Set-SendConnector -Identity "name of the send connector to internet" -MaxMessageSize "30 MB"

Receive connector :

Set-ReceiveConnector -Identity "connector name to receive emails from internet" -MaxMessageSize 30 MB

4.Then Please use the below mentioned command to set the size for the AD site link.

Set-AdSiteLink -MaxMessageSize "30 MB

Hi,

please look carefully at the error Message.Even you increase Message to 30MB its not sure all recipient Accept it.

Default everyone Accept 25MB + bloating during Message transfer (can bloat/increase between 10-30%).

Or else Nithyanandhams great tips applies.

Hi Dan,

Agree with Off2work .Such a valid point.

Same time we cannot expect all the organisations on the other end to receive emails of 30 MB size.In fact we would like to have a look on the NDR which you have received on your end.