I'm trying to write a servent for fun but I am confused as to the need for the push request. My current understanding:

Gnutella servents currently listen on a high port such as 6300 or something. When you do a search and get search results, that communication is going over that port. Once you find a file and want to download it, you initiate an http transfer which happens over port 80. But the problem occurs when port 80 may be blocked for whatever reason. So the servent requesting the file sends a push request to the servent hosting the file basically saying, "hey, you have port 80 closed which means I can't grab it. Please send it to me." Then the servent with the file tries to initiate an http transfer over port 80 to send the file.

Is all this correct? Could someone please explain or point me somewhere with some good information. I've read what I have found but that hasn't been very helpful.