MOVEit Transfer can accept and store AS3 messages and AS3 MDNs that will be processed later by MOVEit Automation or any other AS3 client. MOVEit Transfer, rather than MOVEit Automation, is used in the role of an AS3 server because MOVEit Transfer already serves the function of a secure, Internet-exposed FTP(S) server.
No additional license is required to accept and store AS3 messages and AS3 MDNs on MOVEit Transfer because, according to the AS3 specification, any FTP server can function as an AS3 server. This means that if you have licensed a MOVEit Transfer server, you already have an AS3 server.
AS3 messages and AS3 MDNs are uploaded and downloaded through FTP and therefore are part of the normal MOVEit Transfer file system. All AS3 messages and AS3 MDNs are located in the /Home/...
or /Distribution/...
folders and are otherwise treated as normal files.