Torrent Trackers return port 0 in for peer in peer list

Question

I've began writing a torrent application in Go, and I've now gotten to parsing the HTTP tracker response, however, after trying with several different torrents, each time I've gotten a valid IP address but the port has always been 0.

this is how I parse the compact string response:

func ParseCompact(peerCompactString interface{}) []Peer {
    bytesPeerList := []byte(peerCompactString.(string))
    peerList := make([]Peer, len(bytesPeerList)/6)

    for i := 0; i < len(bytesPeerList); i += 6 {
        ip := net.IP{bytesPeerList[i], bytesPeerList[i+1], bytesPeerList[i+2], bytesPeerList[i+3]}

        port := binary.BigEndian.Uint16([]byte{bytesPeerList[i+4], bytesPeerList[i+5]})
        peer := Peer{
            ip:   ip.String(),
            port: port,
        }
        peerList[i] = peer
    }
    return peerList
}

GET request:

"http://tracker.files.fm:6969/announce?compact=1&info_hash=%60%0C%CD%1BqV%922%D0%
1D%11%0B%C6%3E%90k%EA%B0M%8C&peer_id=MxVpOJmHKKwgobMhNNlS"

the GET request itself seems to be working, as every other piece of information seems valid, one response looked like this: "map[complete:0 downloaded:0 incomplete:1 interval:1874 min interval:937 peers:�� 9�]"

(byte array of answer: [100 56 58 99 111 109 112 108 101 116 101 105 48 101 49 48 58 100 111 119 110 10 8 111 97 100 101 100 105 48 101 49 48 58 105 110 99 111 109 112 108 101 116 101 105 49 101 56 58 105 110 116 101 114 118 97 108 105 49 56 50 48 101 49 50 58 109 105 110 32 105 110 116 101 114 118 97 108 105 57 49 48 101 53 58 112 101 101 11 4 115 54 58 159 148 57 222 0 0 101] )

as the IP address also seems valid (and pingable!) I have to wander, is there a problem in my code, or is the tracker actually returning port 0, and should I try to communicate with the peer on said port?

I've tried going with several different torrent files, each time port 0 was returned.