[SOLVED] Enabling UDP Broadcasts

[YrbkMgr]

I don't know a lot about the innards of networking protocols and such, but to solve a problem, I would like to understand how I can enable UDP Broadcasts, and if that would solve my problem, explained below.

I just bought the coolest Logitech mouse and keyboard (MX Master 3 & MX Keys respectively). They are switchable to be used on up to three different computers by way of a button press. They employ a feature called "Flow" that obviates the need to press a button on the mouse and keyboard- "Flow" allows a user to hold down a key (ctrl) and move the mouse from one screen to another. The only caveat, is that in order to use Flow technology, all the computers have to be on the same network.

As a bonus, the keyboard follows the mouse automatically; meaning that if one presses the control key and slides the mouse to the second computer screen, they keyboard changes to be active on that second computer as well. You can even copy and paste between the computers using Flow. When Flow finds both computers, it works like a dream.

The problem is that flow doesn't always find the computers on the network, or takes a very long time to establish a connection - when I reboot my computer, I have no way to force Flow to find the other computer on the network and re-establish the connection. It can take overnight after a reboot.

Logitech says that "computers on the same subnet that can ping each other using UDP broadcasts, Flow uses a fixed UDP port (59867) to listen for and discover other peers." But "For those computers that are behind routers or firewalls, Flow uses a Logitech cloud service to assist with peer discovery. This discovery technique uses TCP port 443 to communicate with the server and UDP port 59868 to listen for pings from peers. Once peers discover each other, they use TCP port 59866 to establish a secure peer network to send control data

I am behind a firewall. I have an Asus RT-AC3200 router whose firewall is on with manufacturer defaults. I have a Cisco Model DPC3941T DOCSIS 3.0 24x4 Wireless Residential Voice Gateway from Comcast. Its firewall is enabled set at "low" security. I know this isn't an ideal set up, but I'm working on it. I have Norton Internet Security Suite installed with the firewall enabled, and I have Zone Alarm (free). One day, I'll straighten that all out.

What I want to do is be able to reboot my computer (either one) and have Flow find each computer. Using various utilities, when Flow is working and both computers are found, the connection is through TCP port 59866 on one computer's local port and the other computers port communicating is variable, but right now 60258. I've seen it establish discovery with TCP port 443, so I'm assuming that I am not able to use the fixed UDP port to discover peers.

Is there a way to enable my router or firewalls to allow UDP Broadcasts in an attempt to make the discovery of peers quicker? Right now, it can sit overnight after a reboot before both peers are discovered and a connection established.

Does this make sense? Is there a way to force peer discovery faster?

 

[bill001g]

Not sure what you are actually trying to do. If both machines are in your house connected to the same router they are on the same subnet. The traffic never passes through the firewall part of the router. Traffic that stays on the Lan never even goes to the CPU chip in the router it stays in the switch. If you have something like multiple routers in your house or you are trying to do this to a remote machines I don't know what to recommend.

People ask all the time how to filter traffic between pc in their house. With consumer grade equipment you can not do it even if you wanted to.

The only firewalls are on the end machines. I would try to disable the windows firewall in both and see if it works. If it does then you know what you need to try to fix.

 

[YrbkMgr]

Thanks for the reply. Here's what I'm troubleshooting - why do I have trouble with peer discovery with the method logitech is using? Can I configure something to get more reliable peer discovery?

It's supposed to work on my home LAN, and, in fact does. But it doesn't discover peers quickly - annoyingly so. Sometimes for hours.

Flow discovers peers two ways. It will use UDP broadcasting if they're on the same subnet. Mine are on the same subnet. The other way, to avoid firewall restrictions, is to use their cloud service via TCP. This discovery technique uses TCP port 443 to communicate with the server and UDP port 59868 to listen for pings from peers.

When I'm good, that is, I can use the mouse and keyboard as intended because both peers have been discovered, I can see that the the attempt (via resource monitor and other tools) uses TCP port 443 to connect to their "discovery server". That implies that I'm NOT able to use UDP Broadcasting. I'm not sure though.

I would LIKE to find out why there's no discovery using UDP Broadcasting, or at least test it.

 

[SamirD]

So the easiest way to test if it's your systems or the udp lan discovery is to take the two systems and connect them to a simple dumb switch that isn't connected to anything. Then assign each system a static ip and see how long it takes flow to figure it out. If it still takes hours, it's something on each system that's interfering, not the udp discovery.

 

[bill001g]

You can actually see the packets if you use wireshark. You will know if when and if the machines send them and if the other side actually gets them.

This is almost stupid way to do this. Why don't they have the simple way you key in the ip address of the other machine. This has always been my solution when microsoft didn't want to discover things.

 

[SamirD]

But it's 'smart', lol.

 

[YrbkMgr]

So the easiest way to test if it's your systems or the udp lan discovery is to take the two systems and connect them to a simple dumb switch that isn't connected to anything. Then assign each system a static ip and see how long it takes flow to figure it out. If it still takes hours, it's something on each system that's interfering, not the udp discovery.

I can try that, although I have to admit, it's a bit out of my element from a confidence standpoint. I would need to make sure that I set that up correctly. So I have several retired routers that I can use to test; where would I assign the static IP's? In the switch/router interface (192.xxx.xxx.1) or from within control panel in Windows at Ethernet Properties|Internet Protocol?

Is there a place I can test whether UDP lan discovery is functioning properly without using Flow? Some kind of "ping" or something without modifying the topography?

Let's face it, I can't even spell UDP...but I appreciate the thought you've put into this and am willing to try, if you might confirm where I should assign the static IP's.

Last data point: the two computers in question are a Win 10 machine and a Win 7 machine. I can reboot the Win 7 machine all day long and Flow automatically connects/sees the Win 10 machine. But the minute I reboot the Win 10 machine, that's when I have problems. I say that to suggest that the issue/anomaly appears to only happy when one machine is re-booted (the Win 10 machine).

Does that information help in where I should be focusing my attention?

 

[YrbkMgr]

You can actually see the packets if you use wireshark. You will know if when and if the machines send them and if the other side actually gets them.

This is almost stupid way to do this. Why don't they have the simple way you key in the ip address of the other machine. This has always been my solution when microsoft didn't want to discover things.

I have wireshark, but don't really understand how to use it; it doesn't show my network adapter in the startup screen so I decided that's a project for another day.

I agree it's a stupid implementation; I would love to enter specific IP address of the peers.... sigh.

 

[SamirD]

I can try that, although I have to admit, it's a bit out of my element from a confidence standpoint. I would need to make sure that I set that up correctly. So I have several retired routers that I can use to test; where would I assign the static IP's? In the switch/router interface (192.xxx.xxx.1) or from within control panel in Windows at Ethernet Properties|Internet Protocol?

Is there a place I can test whether UDP lan discovery is functioning properly without using Flow? Some kind of "ping" or something without modifying the topography?

Let's face it, I can't even spell UDP...but I appreciate the thought you've put into this and am willing to try, if you might confirm where I should assign the static IP's.

Last data point: the two computers in question are a Win 10 machine and a Win 7 machine. I can reboot the Win 7 machine all day long and Flow automatically connects/sees the Win 10 machine. But the minute I reboot the Win 10 machine, that's when I have problems. I say that to suggest that the issue/anomaly appears to only happy when one machine is re-booted (the Win 10 machine).

Does that information help in where I should be focusing my attention?

A router can work as long as it's not routing anymore otherwise flow might try to use that and it won't be able to because it would go into a black hole and just stay there.

First, I would disable the dhcp on the router. Second I would just assign static IPs to each system in windows in a completely different range than what the router is configured for, like the 10.10.10.x range. So 10.10.10.1 and 10.10.10.2, subnet 255.255.255.0 on both with NO default gateway. If it requires a default gateway, put in 10.10.10.10.

Third, plug in each system to just the lan and see if flow can figure out each system quickly enough. If they can, some sort of routing issue. If they cannot, it's something on the systems.

Besides using wireshark or some other packet monitoring program and then looking at the packets themselves, I wouldn't know an easy way. And honestly, I would even have a hard time to know what I'm looking at.

That's interesting that rebooting just the win10 system gives you issues. If you cannot ping the win10 system or connect to a share on it from the win7 system when this happens, then you might be onto something, otherwise I'd say it's just a bug in flow.

 

[YrbkMgr]

A router can work as long as it's not routing anymore otherwise flow might try to use that and it won't be able to because it would go into a black hole and just stay there.

First, I would disable the dhcp on the router. Second I would just assign static IPs to each system in windows in a completely different range than what the router is configured for, like the 10.10.10.x range. So 10.10.10.1 and 10.10.10.2, subnet 255.255.255.0 on both with NO default gateway. If it requires a default gateway, put in 10.10.10.10.

Third, plug in each system to just the lan and see if flow can figure out each system quickly enough. If they can, some sort of routing issue. If they cannot, it's something on the systems.

Besides using wireshark or some other packet monitoring program and then looking at the packets themselves, I wouldn't know an easy way. And honestly, I would even have a hard time to know what I'm looking at.

Okay, great stuff. Thank you for your help. Just some follow up questions on how to's...

?-Disable the dhcp on the router - done through the browser interface of the router, right?
?-Assigning static IP's, via router interface or through Ethernet properties in control panel?

That's interesting that rebooting just the win10 system gives you issues. If you cannot ping the win10 system or connect to a share on it from the win7 system when this happens, then you might be onto something, otherwise I'd say it's just a bug in flow.

No problems pinging day or night. Odd.

As soon as I get some clarity on where to set the settings (router interface or ethernet adapter properties|internet protocol) I'm going to get to the bottom of this.

Really appreciate the contribution.

 

[DeauteratedDog]

If the two PCs can ping each other, it almost has to be either a firewall issue or just a bug with Flow.

Can you completely shut down both Norton and Zone Alarm and see if it works then?

 

[YrbkMgr]

If the two PCs can ping each other, it almost has to be either a firewall issue or just a bug with Flow.

Can you completely shut down both Norton and Zone Alarm and see if it works then?

Well, I did completely exit ZA and then turned off all Norton (didn't actually shut it down), and there was no change.

But if it were the firewalls, Flow would never work. In my case, it works sometimes. I just can't figure out how to force it to make the connection. When it's working, it's a dream, so I am banging my head on the desk to figure out how to "force" it to connect.

Appreciate the input though.