Sender Port in FILE to IDOC scenario

Hi all,

I am trying to do a File - SAP XI-IDOC scenario.

The idoc which is getting created in XI is having senderport as SAPABC where ABC is my XI system id.

i have not craeted this sender port and i am not able to find it in idx1 tx.code of XI.

Can anyone please tell me how and where is this port is getting created. Will it get genarated automatically by the XI system for posting the idocs?

thanks in adavance

Jagruthi