Web management problems with PTP 250

Operators may experience some problems with web-based management of PTP 250 radios. The web-based management is implemented using a Java program that executes in the web browser, and problems arise for two different but related reasons:

  • The web server in the PTP 250 provides a security certificate to the browser along with the Java program, and the period of validity on the certificate has expired. The default action for the browser under this condition is to refuse to execute the Java code.
  • Most current web browsers will not load and execute Java programs.

We have no plans to provide new firmware for PTP 250, which has not been maintained for several years.

The following popular browsers do not support Java in current releases:

  • Google Chrome
  • Mozilla Firefox
  • Microsoft Edge

We therefore recommend using Microsoft Internet Exporer to manage PTP 250.

Here is a procedure to configure IE to work around the certificate validity problem:

Security implications

Please note that this procedure lowers the security level of the operator’s network. Cambium Networks accepts no liability for any loss which may be caused by executing this procedure. This procedure should only be performed at the operator’s risk.

Out of date certificate

Allow Java to run out of date signature by opening Java console:

  • Windows start menu -> All programs -> Java -> Configure Java

On the security tab click edit site list and then "add". Enter an URL based on the IP address of unit, e.g.

Accept the warning by clicking continue etc.

Java URL.png

The Security tab should now show your device’s IP address:

Enable MD5 signed JARs

Edit the file below (check your install version). You will need to be an Administrator to make changes:

C:\Program Files (x86)\Java\jre1.8.0_131\lib\security\java.security

Change the following line from:
    jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024

    jdk.jar.disabledAlgorithms=MD2, RSA keySize < 1024

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