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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Introduction:

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.

Instructions:

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.