Try connecting from the legacy system to the SAP system using incorrect ports.

Symptoms

Some external legacy systems try to retrieve data from the SAP system. However, when attempting to connect, SAP returns errors similar to the ones below.

• Gateway Trace (SMGW/dev_rd)
  • ERROR => NiIRead: invalid data (peer=SourceIP:port; local=33XX)
• MessageServer Trace (SMMS/dev_ms)
  • ERROR => NiBufIIn: Invalid data (peer=SourceIP:port; local=36X1)

Solutions

Scenario 1.

The administrator of legacy systems such as AICC intends to connect to the SAP via the HTTP protocol on port 3601.

For example, http://<SAP host or IP:3601>.

Upon the legacy administrator’s function call, errors will be logged within the SAP message server trace. The message server, operating on port 3601, is incompatible with the HTTP protocol, and instead, relies on the RFC protocol.

Consequently, it is necessary to verify and replace the HTTP or HTTPS service ports via the ICM, utilizing transaction codes such as SMICM.

The same applies to the Gateway port 3300.

Scenario 2.

If errors are not logged by any service, a firewall will exist between the SAP system and the legacy system.

I would suggest reviewing the logs from the legacy system and then contacting your network administrator.

Additional Info

General ports for SAP communication

• Dispatcher(32XX) : Connecting directly from SAPGUI to Dispatcher.
• Gateway(33XX) : For processing RFC Protocol from legacy systems. (e.g. JCO, .NET)
• MS(36X1) : Handles load balancing the RFC requests and GUI Sessions from Clients. (e.g. JCO, .NET, SAPGUI)

*JCO – Only RFC / .NET – any protocol, such as RFC, HTTP, SOAP.

Checking communication with the legacy system.

• RFC – SMGW(Logged on clients), SM21
• HTTP – SMICM

References

3485271 – ERROR => NiBufIIn:invalid data (len=<nr>;<nr>;max=8388608;hdl70;peer=<IP address: port nr>;local=<port nr>