Unknown or Customized Ports
Many networks contain traffic on ports NNM defines as different traffic types or alternate ports. If the port is not defined, it displays as Unknown. The NNM-services file may be edited to either customize or add the port information to provide accurate reporting for ports on the network.
For example, by default, there are two lines in the NNM-services file that define SMTP traffic. They read smtp 25/tcp and smtp 25/udp. If the organization routinely sends SMTP data over port 2525 those lines can be updated to read smtp 2525/tcp and smtp 2525/udp.