Communication Between Download Manager and FlexNet Operations
The NetSession-based Akamai download manager has been replaced with a Flexera solution. Using the Flexera Download Manager requires that the port 45786 is open, as the Download Manager will use this port. (The Akamai download manager also required an open port, but the port number was different.) The following topics provide more information about the communication between the Download Manager and FlexNet Operations:
Technical Details
The following provides some background information.
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The Download Manager is a Node.js Express application that is installed and runs on the client machine. A Node web server is created on the client machine; the Download Manager process runs on this web server listening on port 45786. |
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The Download Manager uses port 45786 (https://127.0.0.1:45786) for communication with a client and FlexNet Operations server components. Port 45786 was chosen predominantly because it is currently listed as “Unassigned” in the Service Name and Transport Protocol Port Number Registry, indicating that it is not widely used. |
Communication Using JSON Web Token
Information between the Download Manager and FlexNet Operations is exchanged using the JSON Web Token (JWT) standard. Information is securely transmitted between the parties as a JSON object. JWTs are digitally signed using a public/private key pair. FlexNet Operations signs the JWT using the private key, and the Download Manager verifies the digital signature using the public key. Once secure communication has been established, files can be downloaded. Communication between FlexNet Operations server components and the Download Manager is unicast only.
Process
The communication between FlexNet Operations and the Download manager can be broken down into the following phases:
Phase 1: FlexNet Operations performs the following steps:
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Prepares a list of URLs that the Download Manager needs to download |
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Calculates the MD5 digest of the URLs |
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Using the MD5 digest, prepares a JWT and signs it with the corresponding private key |
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Securely sends the signed JWT to the Download Manager |
Phase 2: On receiving the list of URLs, the Download Manager does the following:
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Recalculates the MD5 digest and validates it against the JWT using the public key |
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If it finds the JWT to be valid, proceeds with the download |
Phase 3: The Download Manager reports the status of the download progress back to FlexNet Operations.
Summary
Port 45786 is used for both inbound and outbound communication between the Download Manager and FlexNet Operations server components. Information exchanged between the Download Manager and FlexNet Operations can be verified and trusted because it is digitally signed, using the JSON Web Token standard. Port 45786 is an integral part of the client-server architecture and must be open to enable communication between FlexNet Operations and the Download Manager.