I'm trying to figure how to send UDP messages to Max from other programs.

I have a local area network on which I'm running several Macs and a PC with Max on each of them.

I'm able to send and receive UDP messages between the different instances of Max.

I'm also able to send UDP messages from Max to external programs like PacketSender.

I'm NOT, however, able to send UDP messages from external programs like PacketSender to Max. 

And for that matter, I cannot send UDP messages at all between external programs (e.g. PacketSender on Mac to PacketSender on PC).

Any ideas why Max is able to send UDP successfully but no other external programs can send UDP?

Would this be a router or firewall issue? I'm using a Cisco DPC3939B.

I'm trying to figure how to send UDP messages to Max from other programs.

I have a local area network on which I'm running several Macs and a PC with Max on each of them. 

I'm able to send and receive UDP messages between the different instances of Max. 

I'm NOT, however, able to send UDP messages from external programs like PacketSender to Max. 
And for that matter, I cannot send UDP messages at all between external programs (e.g. PacketSender on Mac to PacketSender on PC).

Any ideas why Max is able to send UDP successfully but no other external programs can send UDP?  

Would this be a router or firewall issue? I'm using a Cisco DPC3939B.

Windows 10 on PC
Mac 10.11.6

I'm trying to figure how to send UDP messages to Max from other programs.

I have a local area network on which I'm running several Macs and

Can't send UDP from external programs to Max