Getting un-binded ports using python

Question

I am using the below python code to get two available unbind-ed port. I am running another c++ program, which binds to port 8000 and waits for a message to come, before running this program. Still it gives port 8000 as unbind-ed. I am sure the port 800 is listening.

The code is not catching any exceptions.

Any help please.

def get_next_port():
    global udp_port
    global result
    global port_list
    global number

    try:
        print "try"
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.bind(('', udp_port))
        port_list.append(udp_port)
        print udp_port
        udp_port = udp_port+1
        number = number+1
        sock.close()
    except socket.error as msg:
         print "except"
         if msg.errno == errno.ECONNREFUSED:
            print "already binded"

while(number < 2):
    get_next_port()