Receive UDP broadcast packets on localhost when network is down

Question

I am using python to create a UDP client to broadcast messages as per code below. this works as expected. however when the network is down, I would still like the server running on the localhost to receive the UDP packets. any way this can be done.

try:
    s1 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s1.bind(('', 0))
    s1.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
except socket.error:
    print 'Failed to create socket'

I put the following in a loop

try:
    s1.sendto(msg, ('<broadcast>', port))
 except:
    print 'Failed to sent message'