Disabling TCP timestamps

The OS fingerprinting probe examines the remote server's implementation of TCP timestamps. Timestamps provide the attacker with a means to guess the operating system of the target.

For z/OS®, TCP timestamps can be disabled by executing the following steps:
  1. Find the TCP configuration data set, named as Profile.TCPIP or similar.
  2. Edit the TCP configuration data set by appending NOTCPTIMESTAMP in the line TCPCONFIG.
  3. Using a user with CONTROL access, run VARY TCPIP,SYNTAXCHECK, tcpConfigurationDatasetName to validate the syntax of the configuration file.
  4. Using a user with CONTROL access, run VARY TCPIP,,OBEYFILE, tcpConfigurationDatasetName to apply the changes.
For more information, see: