TL,DR: Internet services vary, and some types are more suitable than others for setting up an EchoLink node. Not every type of ISP will work successfully with EchoLink.
Modern Internet service providers (ISPs) which serve residential areas now come in several popular forms, with varying levels of service:
- Landline (DSL)
- Cellular (Wireless)
For each of these service types, you typically have a router in your home — either leased from the ISP, or owned by you. All of the PCs and other devices in your home
connect to this router, either with Ethernet cables or over WiFi. In many cases, the router also serves as the WiFi access point.
Each of the devices in your home has a separate private IP address; but when communicating over the Internet, all of these devices share a single external IP address.
In fact, one of the purposes of the router is to allow these devices to share this address. This is more cost-efficient and secure than assigning a separate external address to every device.
Sharing an address works fine, until you try to set up one of your PCs as a server, so that it can accept packets coming in from the internet. To make this work,
you often need to set up special rules in the router (called port forwarding rules) which tell the router to direct all messages coming in on a specific port, to
a specific PC in your local network.
However, if you're using Cellular or Satellite-based internet service, such as T-Mobile or Starlink, it's likely that the ISP is using a technique called CGNAT — carrier-grade network address translation.
This arrangement means that you and other customers are sharing a single public address. Depending on the specific service, you might not be able to set up port forwarding rules
in this situation, because you don't own or manage the router; the ISP manages it, and it's being shared with other customers. (Some of these other customers might even be using EchoLink!)
If you can't avoid using a CGNAT service for your EchoLink node, one option is to subscribe to a VPN service that supports port forwarding. VPN stands for "virtual private network";
it's a way of digging a tunnel through your ISP, to a server out on on the Internet which has a more direct connection. With this arrangement, you can set up the port forwarding
rules that EchoLink requires. VPN providers typically charge a small monthly fee for this service; one example is PureVPN. But be sure to choose a VPN service that supports
port forwarding on a dedicated address — look for that exact phrase when signing up.
If you use a CGNAT service (such as LTE), you can also check with your ISP to see if it offers an option such as "public IP". This is sometimes available, usually as an upgrade option, and it may allow you to
set up port-forwarding rules in your router in the usual way.
Incidentally, even with cable or fiber-based internet service, VPN can be a good way to run a second EchoLink node over a single Internet connection, to work within the limitation
that every node must have its own distinct public IP address.
Frequently Asked Questions
Q: When I'm setting up port forwarding, which ports need to be forwarded?
Q: Instead of a VPN, can I use a public EchoLink proxy for my node?
A: EchoLink requires two ports to be forwarded: UDP 5198 and UDP 5199.
Q: I'm already running a node on a cellular CGNAT service, and it seems to work fine. What's the issue?
A: A proxy is great temporary solution for running your node when you're in a public place
on a shared Internet service. But for a 24/7 EchoLink node, you'll get better reliability using a VPN.
A: It's likely that your node is unreachable — that you're only able to initiate EchoLink connections,
and not able to accept them. You can use the Router/Firewall Test Page to confirm this. This is a poor experience for anyone
trying to connect to your node, and it may lead to your node being de-listed from the EchoLink system.