Debugging My SmartLink Connection – for newbies
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Debugging My SmartLink Connection – for newbies

This video is for the SmartLink user who does not have any experience in LAN Networks. We go over a bit of the basics of a computer network and then the things to look for in debugging why your FlexRadio SmartLink connection may be failing.

Video Transcript

This video’s full transcript has been provided below for your convenience.

Hi, it’s Mike from FlexRadio. And in this video, we’re going to do a “How do I debug my SmartLink if I’m having issues and I know nothing about networking?” We’re going to keep it incredibly simple. You don’t have to worry about all these strange terms like universal plug and play, well a little bit, you’ll have to worry about that one. Ports, port forwarding, IP addresses, VPNs, and etcetera, etcetera. If those are all strange terms for you, this video’s for you. If you know what all those terms are all about, you can stop watching right now. Just hit the like button for me on the video here in YouTube and carry on, go work some great DX somewhere. But for the rest of you, hopefully we can teach you how to debug it when SmartLink fails. Now, I’m assuming that you’ve already had SmartLink running, or maybe you’re having an issue, getting it going.

I highly recommend, you look at chapter nine of the SmartSDR users guide. Version three users guide is in chapter three, I think version two is in chapter eight. And I will put the links to those documents in the show notes, as well as the video on how to set up SmartLink for yourself. So as I said, SmartLink problem solving for newbies, and this is going to be pretty good. I’ve been asked to do some videos that start right at the beginning for somebody that doesn’t know anything about networks and such. And the stuff I’m going to teach you today is going to be incredibly valuable for yourself. You’re going to learn a little bit about a network and this will not only be good for FlexRadio SmartLink, but it’ll actually help you If you’re debugging something else in your home network, like your kids’ gaming doesn’t work.

And I’ll just give you the terms that will help you understand it. When somebody says, “Well, go check your port forwards.” So I’m going to teach you a little bit about IPV4, that’s network addressing. There’s also V6. I’m only going to mention that it exists, so don’t worry about it right now. How SmartLink works at a really high level, and do I need a VPN? No, you don’t need a VPN, I don’t actually want you on a VPN. VPNs are a wonderful tool, they are complicated to set up if you don’t understand how the communication works. And even though you may have a friend help you with it, you want to make sure that they leave you good notes, or that they’re around for a while, if you have a problem a year or so from now, and something changes, so they can quickly log in and fix whatever they might have customized for you.

To use a FlexRadio remotely, SmartLink is by far the easiest plug and play tool, but it’s not the only way to do it. And this is where VPNs come in and a lot of our users and customers have chosen their own roll your own road, because that’s ham radio, right? We do it all sorts of different ways and there’s nothing wrong with that as well. So, and then we’re going to go over a little bit about SmartLink. So a few definitions. And, these are really key. So the router, every house has a router and every house should only have one router. And the router is the switchboard. And if we go back to old school, telephone switchboards, that’s what the router does. And when someone calls your network like a radio user, or maybe yourself while you’re on vacation, you’re going to call your router or your switchboard.

And it’s going to say, “Hey, SmartLink user’s calling, and we have to make sure that that call gets directed in the right direction.” And we do that with a tool called port forwarding. And the good news is, you don’t have to worry about it because we have tools to set it up automatically. As I said earlier, SmartLink is the utility built into SmartSDR that allows you to use your radio remotely and easily, and maybe even share your radio with your friends. An IP address is that funny looking number. And it’s the collection of four, three numeric numbers like 192, 168, 100.1, and it’s called dotted notation.

“The key point of everything we’re going to go through today, is about keeping it very simple, and keeping it just the way it came out of the box, without customizing anything.”

A port address is a special number between one and about 65,000. So you just have to remember they exist. And we’re going to worry only about one or two of those. And some examples of port numbers are on the picture on the side. It’s the port we actually want to address on the IP address, but don’t worry about that a little bit further on, and believe it or not, there’s a lot of different ways to send data over a LAN, a local area network.

We only courier about two of them, UDP and TCP, and they’re called packets, because they’re packets of information. Let’s say one is a registered letter and the other one’s junk mail, not quite that bad, but the registered letter we want to know, got to one place and we let the other person know and the UDP packet or the fire and forget missile, is sort of like junk mail. We’re going to send it to your house and hope you open it. And so that’s really the difference between UDP and TCP packets.


IPV4, Internet Protocol Version Four. It’s been around forever, and there’s another one called Version Six. Now we don’t support anything with Version Six at this time, it’s something we really have to look at. And for some of you, especially in Europe, Version Six is the only method you can get right now.

And unfortunately we don’t support it, meaning we don’t work with Version Six only. And that’s the sad news as of today, which is mid July 2021, just as a reference. So, as I said earlier, TCP/IP, it’s just a collection of protocols used to communicate over your network. And it’s how you get your packet of computer information, from one computer to another. 

Now, another neat thing is we have LANS, that’s the local area network that’s inside my house or your house. And we have WANs, wide area network. And that’s the part on the outside part of your router. And so just remember inside outside, wide area network, local area network, and all the stuff we’re doing today is on the local area network. As I mentioned before, an IP address is this dotted notation and the WAN address has a number, it could be 24, which happens to be mine.

It’s a variety. There’s a lot of numbers. There’s a lot. Most home numbers begin with 192. 168. Sometimes you’ll see 10. and a few others. You can look up what’s generally routable, they’re called routable versus non routable addresses. But, for most of you that are really new to this, of a very simple network set up in your house, I guarantee it probably starts with 192.168, either 1. and a unique number or 0. and a unique number. And the other thing you want to keep track of is the first three numbers, 192.168.1 is an example as I’m showing here in the third bullet or the fourth bullet, that’s your subnet. And if we mention subnet, the subnets, just my home LAN. And most home systems have one subnet. That’s all you want. And if you ever hear somebody say something about double NATed, well, you probably have two subnets and you probably want to call us. So we won’t even go there because it’s just not worth the time and it can be complicated.

“In the FlexRadio world, we need to know two port numbers, so that when you’re out on vacation and try to connect your radio, the Maestro or your computer needs to know what two port numbers to use to call home.”

So how do I get an IP address? Who’s the post office that gives me this? Well on the wide area network, your ISP, your internet service provider, will provide you that. And the router does that automatically. Again, the WAN address is provided by your ISP. And it may change. You really don’t care. It doesn’t much matter for us and SmartLink. As I said earlier, only one router per household. Another term for the router, you might see when you’re poking around is something called the gateway. 90% of the time, they are the same piece of hardware and they will have the same IP address. Something like And don’t worry if your eyes are glassing over at this point in time, you don’t have to remember all that. The key point of everything we’re going to go through today, is about keeping it very simple, and keeping it just the way it came out of the box, without customizing anything.

Every piece of hardware in your local area network has its own IP address. Again, 192.168.1.. And that includes the radio, your Maestro, your iPhone, your apple watch, or any other WiFi or LAN based device. Those addresses are assigned by the router. And it’s the post office for your LAN. And what happens is, when you connect to the WiFi is a great example, or you plug a LAN cable into a piece of hardware, like even the back of the radio, there’s a routine that happens. And the radio connects onto the local area network. This is all automatic and says, “Hey, I’m here, I’m here. I need an address. Somebody give me an address.” And the router says, “Here you go. Here’s one that’s not in use.” And the router’s in charge of keeping those, keeping order among hardware and not shipping out duplicate IP addresses. And that works really well.

And you only want one post office, that’s the DHCP server, on your whole LAN. And if you have two really strange things happen and things break, and it’s really hard to diagnose, so one router, one gateway, and you’re all good to go. Where does this break? This little sidebar here, when you sometimes get range extenders and meshes, we’ll segregate your network into two subnets. And if we do that, it’s not really good. It can cause problems. Everything will look like it’s working, but in our world, it’ll cause problems. And you really don’t want that.


If that device like a mesh and I highly recommend a mesh over a range extender, and you can find those on Amazon, you want to run it in a mode called bridged. And bridged just means it behaves like one big happy family, everybody in the same house. And there’s a whole lot of ways if you have to extend or reach further, feel free to ask us on Facebook or even more in the Flex community. “Say, “Hey, my ham shack’s like a hundred feet out in the back forte, what’s the best way to get my LAN down there.” We’ve got a lot of great ideas around the Flex community.

I said one DHCP server per household, and that’s also the router, and of course the gateway. By the way, you know why we call it a gateway? Because that’s our gateway to the outside world. And that’s how we communicate and get our news, Netflix, etcetera. So there’s two parts of a communications packet. One is the address, the IPV4 address. And as I said, here’s an example of And you know what, we call it dot not periods. And there’s also a thing called a port number.

And every device has a port number if it’s communicating, that you target, it’s like an extension. So just keep that in mind. It just gives us a lot of flexibility. We’re only going to be worried about two port numbers. And if you look at the bottom line of the slide, we have and then a colon. And the next four or five digits somewhere between one and 65,000, 65535 to be exact is the port number. That’s all you need to know, how to read this, which IP address, colon port number. It’s the only part you need to know. And all of the messages on the network get moved using this little piece of information. So a bit of a summary, we have a router that’s connected to the internet in your ISP, we have a DHCP server, that’s the dynamic host configuration protocol, strange name, but that’s the one that gives everybody an IP address.

And all of our toys are automatically connected to our LAN, or our WiFi, to get an IP address. We have nothing manually configured. And if your buddies come over and say, “Hey, let me just manually configure everything, it’ll work great.” It will work great. But if something changes, you’re going to have to get them back to fix it. And that’s what we’re trying to avoid. If we leave it all on automatic, it actually works really well, because the FlexRadio devices are designed to, it’s called advertise themselves on the network and say, “I’m here, I’m here.” And so when you bring up SmartSDR, it can see the radio broadcasting, “I’m here, I’m here.” And then it connects, and that’s how you get SmartSDR connected to the radio. That’s why it just sort of seamlessly works. And we use IP addresses and ports together, as part of the mail addressing. Think of it as a street address, a zip code or a postal code, or something like that.

So what is port forwarding? Well, as we said, all the communication does require a port, a specific number. Anytime you web browse by default, we use port 80. And if we secure web browse, if it’s a secure webpage, which most of them are today, we generally use port 443. Do we care? No. It’s just that it happens. Well, in the FlexRadio world, we need to know two port numbers, so that when you’re out on vacation and try to connect your radio, the Maestro or your computer needs to know what two port numbers to use to call home. Well, you don’t need to know it, but it has to be able to communicate through the router. And this is sort of a hard part to comprehend. So we come in from the outside world, we’re on a beach somewhere, we’ve pulled out our iPhone, and we want to connect to our radio because we got a text from somebody that said there was great DX on, but the port forward says, “Hey, it’s inbound on port 22000,” because that’s we said, it doesn’t.

And then the router says, “Okay, I’ve got some information on port 22000, where does that need to go? Oh, it needs to go to the radio.” And it automatically sends it to the radio. And it does that for the TCP connection and the UDP connection. Perfect. And I know this is probably sounding confusing, but bear with me, we’re going to get to the part that tells you how to see if it’s really correct or not. But I wanted to give you under the covers, how it works a bit. When you’re away on vacation or your friend wants to connect to the radio, they start up a SmartSDR. Our clients, like SmartSDR for Windows, SmartSDR for Mac, DogPark SDR, SmartSDR for iOS, and call the radio.


SmartLink knows where to find your radio automatically. That’s just something you do not need to worry about. That’s just all automatic. And then it calls you right here. Here’s your router. And over the internet, it’s all magic. It connects to the WAN side on two port numbers, these are, I think we used 22000 and 21000 by default. In fact, yes we are right here. This part right here, I’ve got recorded 21,000, 22000. It goes through the router automatically, and it connects to the radio and we’re on the air. So what do we need to check if we have a problem? We want to check to make sure that we have this test button in SmartSDR. This is the type of thing you need to do before you leave. And if you test that, that light will turn green. If it turns red, we need to understand why.

And you’re going to have to log into your router to do that. And you’re going to have to use Google to figure that out. And some smaller ISPs use something called Carrier Grade NAT, Carrier Grade Network Address Translation. And if your ISP does that, SmartLink will not function. You’ll have to work with us on that and see if we can even, we’ll tell you what to ask your ISP. The odds are, some of them say yes, most say no. It certainly doesn’t work on StarLink as of today. So we’re going to set up SmartLink. This is in chapter nine of the manual. You want to look at your router and make sure that universal plug and play is turned on. And if it’s not, you can turn it on. There’s probably a button that says enable universal plug and play.

And if you can’t find it, you’ll have to Google how to do it. You may have to call your ISP. A few caveats, is it a risky thing to do? The purists would say yes, it should probably be turned off. I’ve had it turned on forever. It’s never been an issue. Does opening ports cause security issues? No and yes. It can, even though you open a port, it doesn’t open your firewall to anything happening.

So say I opened a port like port 7373 on my router and just said, “You have full access to my internet inside my house.” It’s not going to do anything. It’s like having a phone hooked up to somebody’s desk at your switchboard, but there’s no phone there. It’s just a Jack on the wall. So nothing will happen. You actually need a program to answer the call. So that’s what universal plug and play does. And as I keep saying, this is for the beginners. We want to make sure that it works as seamlessly as possible. And that’s why we want to use universal plug and play turned on our router. Because the radio will send the right commands, to the router, to have the correct port forwards done.

And this is what makes us so key, that the radio automatically sets up your router for you should never even have to log into your router. We’re here because it doesn’t work. So we may ask you to log into your router and look for a table. It’ll be called universal plug and play and it’ll have some numbers in it. And if you send that to us, we’ll be able to figure out a whole bunch of things. So SmartLink’s not working, and this test is red. Sorry, I didn’t get a red icon here. It’s either red or green. Great. Green is good. If it stays red, don’t bother going any further, because it’s not going to work. Don’t go on vacation and assume it’s going to just fix itself. There’s a couple of quick options you can do. Power cycle the radio and power cycle your router. Unplug them, turn them off, shut them down, wait 20 seconds, 30 seconds, plug them back in and see if that clears it.

You run the test again, and if it’s still red, then we need to go a little bit further. Generally, if it had worked before and doesn’t work now, this works all the time. If it’s never worked and it’s your first setup, you may have to give us a call, but I’ll give you a few more things to look at. It’s still red, now, remember we looked at this table. This is from my PF sense router. And right here, we have We’re just going to look at these last two written lines because I have two radios on my network and it says .76. The other ones .78. So let’s just not look at that. Well, if we look at SmartSDR in the setup panel, we’ll see that right here in this green box, my radio IP is Good. Those match. And this 21000 and 22000 are these 21000 and 22000, and it says forward TCP port number 21,000 to 4994.

And this is the slide you want to look at a little bit. TCP port 21000 on the LAN side, TCP to 4994.4994, 4994. Good. That one works. For UDP port, UDP port 22000 to 4993. 4993. Good. And of course, we’re going to get a green light when we run this test.


If this is all configured correctly, then you should be good to go. And if not, then you’ll probably have to open a support case. If you have a minus one here, you’ll have to reboot both items and see if that clears everything up. But also, log into your router, you will probably have to Google, my TP link, whatever router you’ve got for your ISP. And they’ll be chats on it, and find the table. It’s probably maybe under advanced setting.

And by the way, you’re just poking around. You’re not going to change anything, you’re not going to hurt anything, it’s okay to look. The current universal plug and play rules. There may be a bunch of these, because Skype can open a few of them. But look for the ones that say FlexRadio SmartLink TLS, by the way, TLS is a secure connection. And then the UDP port, these are the two you want. And so we want to check the IP address through this, 76, .76 and this and this. Got it? And that’s the part we need your eyes on. If you’re still stuck, take a screenshot of these two screens and open a support case with us. We want to see the status, the universal plug and play status. And we want to see this screen here. You can use your phone, but make sure it can focus, then you get all the information, the great screen capture tool I use to do all these diagrams, It’s free for windows. And I think it’s like, I bought it for the Mac because it’s so great.

It’s called Greenshot and you can get it at the web link I’ve shown below. Oh, it’s even built into windows. Just Google, how do I take a screenshot with windows? There’s lots of ways to do it. Windows has the sniping tool, S-N-I-P-P-I-N-G, Sierra, November, India, Papa, Papa, India, November Golf. That’s also built in. I like Greenshot, because it hooked up to my print screen key. So I just hit the print screen key and away I go. This is the information we do see, we can help you go further. I know probably some of your friends, more advanced set of friends say, “Oh, you need to hard code everything.” Well actually you don’t. If you have universal plug and play turned on, and your radio is using DHCP, which means it’s all automatic, rebooting both devices usually resolves most SmartLink issues.

It’s because something changed, and it just brings them back in sync. If you hard code the IP address, like you set them up manually, it doesn’t always clear things when you reboot stuff that something else changed, that is not aware. And we see this quite a bit where the radio is hard coded, or you get a new router, this is a really good one. Like the ISP gives you new hardware, instantly everything will break. If you follow this rule, and universal plug and play, UPnP is turned on in the router. It will, excuse me, it will always work, just DC power cycling should bring it all back in line. So Ken Wells asked me to mention this in support, uninstalling and reinstalling SmartSDR, won’t help you in this issue. In fact, it very seldom happens, helps fix things.

Now, maybe in PowerSDR, it did, because it reloaded all the software on the radio, but all reinstalling and uninstalling SmartSDR is reinstalling the client software. It actually, as I said, very seldom resolves any issues. You can, if you have some VSP problems, you can just give us a call. Well, we’ve got some cool tricks to get through them in a hurry. If you know what you’re doing, you’re certainly welcome to play around and try things out and start over. But if you just want to get it working, our support team is amazing. I’ve seen callbacks in less than five minutes, usually in or 10 minutes, watch your emails about every time it falls apart and people don’t get an answer. It’s generally related to the fact that the reply email got swallowed up in a spam filter. So that’s, you know, we’re really here to help.

I think we do an amazing job of it. I think we’re probably better than most amateur radio vendors in the world. And of course we have support in Europe as well in English and German. So in summary, I know I’ve said it a bunch of times, make sure universal plug and play is turned on on your router. Make sure that SmartLink is set to automatic mode, not manual. You want to carefully, if you get messed up, just take a minute, walk through chapter nine in the manual. If you need to print it off, just print off chapter nine and go through it like a Heathkit project and check everything. And then lastly, you can open a support ticket at Again, I’ll put that link in the show notes, so you can get there fairly quickly. And that should keep your SmartLink running.

I know it’s been a bit of a long video, certainly much longer than I wanted it to be. And by the way, you now know how most other programs work. We have IP addresses and ports, and one has to talk to the other, and it’s actually that simple.


So thanks for taking the time to join me. And I hope it helps you out. Feel free to send me your comments, hit the like button, our marketing guy’s telling us to make sure we hit the like button it’s important, and get on the air, make some contacts because you can do it. 73. This is Mike VA3MW. See you later.

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