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ERROR: HTTP request on main port

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UpdatedSeptember 30, 2025

Summary

RLM will report non-licensing traffic that is sent to the RLM server port. This is to be informational to the RLM administrator on the server, and can be used during troubleshooting. This message can be disregarded during normal operation of RLM.

 

Currently these error messages will be printed to the console, or debug log (if enabled), by default. As of the current RLM release there isn’t a way to disable these error messages.

 

Server Ports

RLM Server will bind to 3+ server ports during normal operation:

  • The RLM server port
  • The ISV (Software Vendor) server port(s)
  • The RLM web administration port (optional)

 

For more information about RLM server ports please see this knowledge base article.

 

Error Message

Example error message

The error message itself can be broken into 3 parts for understanding:

  1. (rlm) ERROR: – This indicates that the error is from the RLM server, and isn’t from the system or one of the ISV servers.
  2. HTTP request on main port – This indicates that non-licensing traffic has reached the main RLM server port (default port 5053).
  3. from IP [IPv6 addr:port] – RLM will identify the IPv6 address of the client device, and the source port that the client is communicating on.

 

Common Causes

These are some of the common causes of this error message. Note that this is an example list, and we cannot list every possible traffic source.

  • The most common cause is a user trying to access the RLM web administration interface, and entering the wrong port number.
  • Port/security scanning software.
  • Traffic for another application (common if port-forwarding has been misconfigured on a router).

 

RLM and RLM
Activation Pro

What’s the difference?

Reprise License Manager (RLM)

Software License Manager

RLM provides runtime checking that verifies that your application is licensed to run and that the current usage of your application is within the limits you have ser every time your application runs.

As a Software publisher, you integrate RLM into your product, and RLM keeps track at runtime of who is using the licenses of your software.

RLM can do this entirely within the client library (linked into your application), or, more commonly, your application makes a request of the RLM Lincese Server to check out a license.

The lincese server runs either on your customers network, or in the cloud if you are using our RLMCloud™ service.

RLM provides runtime checking that verifies that your application is licensed to run and that the current usage of your application is within the limits you have ser every time your application runs.

RLM Activation Pro

Software Activation Manager

Activation Pro is
used once when your customer purchases your software in order to retrieve the license which is specific to that customer.

Software Activation’s purpose in life is to get the licenses for your product to your customers with a minimum of fuss.

Activation Pro also has a server component wich we call the activation server.

Your application contacts the activation server and supplies a short text activation key, and in exchange, the activation server returns the license which enables your product.

Generally, this is done once, right after your customer purchases your software, not every time your software is invoked.