Tjyylli

I have two subnets that are connected through a Palo Alto 850 firewall.

I've been working with my networks guy and he says he "set up a static RP, enabled IGMP PIM on the interfaces and PIM permitted neighbor is set to any".

Nevertheless, a trivial multicast server on one subnet fails to pass data to a trivial client on the other. The same trivial client works on the same subnet as the server. Client and Server are running CentOS 7; firewalld is disabled on both; server is running in a VMware VM. The working client (on the same subnet) is another VMware VM, but the client on the other subnet is a stand-alone workstation.

Trivial Client:

#! /usr/bin/python



from __future__ import print_function



import socket

import struct

import time



def Log(*args, **kw):

    print(time.strftime("%H:%M:%S"), *args, **kw)



class Monitor(object):



    def __init__(self, name="Client", args=(), kwargs={}):

        self.args = args

        self.kwargs = kwargs



    def start(self):

        self._run(*(self.args), **(self.kwargs))



    def _run(self, *args, **kw):

        group = kw["mgroup"]

        port  = kw["mport"]



        Log("mcast group", group, "port", port)

        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)

        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

        sock.bind((group, port))



        sock.settimeout(5)



        mreq = struct.pack("4sl", socket.inet_aton(group), socket.INADDR_ANY)

        sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)



        count = 0

        while True:

            try:

                packet = sock.recv(8192)

                count += 1

            except socket.timeout:

                Log("mcast timeout")

            finally:

                if count > 0 and count % 10 == 0:

                    Log("mcast received", count, "packets")



def main(kw):

    client = Monitor(kwargs=kw)

    client.start()



if __name__ == "__main__":

    kw = { "mgroup" : "239.1.2.49", "mport" : 20000,

           }

    main(kw)

Trivial server:

#! /usr/bin/python



from __future__ import print_function



import socket

import time



def_mgroup = "239.1.2.49"

def_mport  = 20000

def_rate   = 2



def usage():

    import sys

    print("Usage:", sys.argv[0],

          "[multicast group address [multicast port [rate]]]")

    print()

    print("    multicast group address - default", def_mgroup)

    print("    multicast port          - default", def_mport)

    print("    rate                    - default", def_rate)



def main(**kw):



    mgroup = kw.get("mgroup", def_mgroup)

    mport  = kw.get("mport",  def_mport)

    rate   = kw.get("rate",   def_rate)



    sleepdur = 1.0 / rate               # divide by zero if you ask for it



    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)

    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 10)



    npackets = 0

    while True:

        sock.sendto("robot", (mgroup, mport))

        npackets += 1

        if npackets % 10 == 0: print(time.strftime("%H:%M:%S"), "sent", npackets)

        time.sleep(sleepdur)



if __name__ == "__main__":

    args = {}



    import sys

    try:

        if len(sys.argv) > 1:

            args["mgroup"] = sys.argv[1]



        if len(sys.argv) > 2:

            args["mport"] = int(sys.argv[2])



        if len(sys.argv) > 3:

            args["rate"] = int(sys.argv[3])



        main(**args)



    except Exception as e:

        print(e)

        usage()

Neither of us really know what we are doing. Can someone shed some light on this?