How to test if Multicast is working on your network

Q. How can I test to see if multicast is working on my network?

A. Generally unless disabled on your switch or routers, it should be enabled. However many router and switch administrators will disable multicast to guard against flooding and unwanted traffic on the local network. 

See the following Wikipedia page on Multicast for information on this method of distributing data:


To start we have to configure a sender, for this you will need 2 small programs designed to send and receive using multicast. In this test will will configure two workstations, the first to send a large file and the second to receive it. 

Using a large file is a good way of really testing multicast as we often only transfer large files. So a large ISO or some type of media file is just fine for testing. 

Download the two programs upd-sender.exe and udp-receiver.exe from here: and the documentation is here:


1) Please these 2 files in say the root of C drive of each machine to be used in this example. 

2) Open a CMD Prompt as Administrator on each machine

3) On the repository or sending computer run:

C:\udp-sender --full-duplex --min-clients 1 --max-wait 480 --nokbd --mcast-all-addr --portbase 2232 --ttl 1 --file Mylarge.ISO

where MyLarge.ISO is some reasonably large file. Replace this whatever you like. 

4) On the receiving computer open a CMD prompt as administrator

C:\udp-receiver --nokbd --mcast-all-addr --portbase 2232 --ttl 1 --file MyLarge.ISO

Check the file was sent ok. On the reciever it should finish with output of "Transfer Finished" after a few minutes depending on transfer speed and size of the file. 

Now if the one to one relationship of multicast works we can now try adding another receiver or client by increasing min-clients parameter and testing the one to many relationship of multicast.

1) On the repository computer run:

C:\udp-sender --full-duplex --min-clients 2 --max-wait 480 --nokbd --mcast-all-addr --portbase 2232 --ttl 1 --file MyLarge.ISO

2) On two client computers run:

C:\udp-receiver --nokbd --mcast-all-addr --portbase 2232 --ttl 1 --file MyLarge.ISO

If the test file is received by both computers configured to receive then in theory you dont have any issues with multicast. 

However, If you receive any issues or errors during the transfer then its time to start look at the internal network infrastructure and any other issues that may affect multicast. Such as routers / switch configurations and number of hops between end devices. 


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