Explaining of 2 successful exception cases (for TCP traces) using Foreign Ports on a SmartTrace

Document ID : KB000009384
Last Modified Date : 14/02/2018
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Upon request of a SmartTrace, PT command, of a TCP/IP stack, placing a port on field Foreign Ports, having fields Foreign Host, Local Host, and Local Ports a value or not, Foreign Ports is not respected for packet filtering,

as the trace result shows other packets with other ports that have not been specified.


On the SmartTrace help screen, Foreign Ports applies to both TCP and UDP, and not only to UDP, as follows:


Foreign Ports is the port name or number used by the remote endpoint in a TCP/UDP connection. The

following formats are supported:


  • The explicit specification of a well-known port
    name that is designated by the Internet Assigned
    Numbers Authority (For example, Port 21 is FTP )

  • A range of port number (0-65535)

  • A comma-delimited list of either or both


There are 2 exceptions where Foreign Ports for TCP is recognized:

Exception 1:
Foreign Ports for TCP is recognized if the "Create Multiple TCP Connection Trace?" is set to YES.

Exception 2:
"PT" traces initiated via the connection list panels (/CONN*) uses the Foreign Ports because connection lists are based on whatever values are found on the connection list entry.