Standardizing In/Outbound SMTP Configuration Maximum message size in bytes with Exchange In/ExternalDsnMaxMessageAttachSize ?

Hi,

I have Exchange Server 2010 and Symantec Messaging Gateway that is running in house, but the email size limitation somehow differs and caused some confusion.

So in this case:

Exchange Server 2010 values:

[PS] C:\>Get-TransportConfig | fl *Max*
MaxDumpsterSizePerDatabase      : 50 MB (52,428,800 bytes)
MaxDumpsterTime                 : 7.00:00:00
MaxReceiveSize                  : 50 MB (52,428,800 bytes)
MaxRecipientEnvelopeLimit       : 5000
MaxSendSize                     : 50 MB (52,428,800 bytes)
ExternalDsnMaxMessageAttachSize : 25 MB (26,214,400 bytes)
InternalDsnMaxMessageAttachSize : 25 MB (26,214,400 bytes)

[PS] C:\>Get-ReceiveConnector | fl *MaxMessageSize*
MaxMessageSize : 100 MB (104,857,600 bytes)
MaxMessageSize : 100 MB (104,857,600 bytes)

[PS] C:\>Get-SendConnector | fl *MaxMessageSize*
MaxMessageSize : 100 MB (104,857,600 bytes)

Symantec mail Gateway (Brightmail appliance) values: 

"Inbound SMTP Configuration Maximum message size in bytes": 20971520 bytes
"Outbound SMTP Configuration Maximum message size in bytes": 20971520 bytes

Which values should I standardize and make it the same ?

Does it requires any outage or reset of the server ?