Beyond Reach

Miln App Membership includes true reachability verification.

Beyond works out where your Mac is on the Internet and if others can reach you. What does this mean and how does it work?

Internet Addresses and Private Networks

Every Mac connected to the Internet has an Internet Protocol (IP) address assigned to it. This IP address is provided by your Internet Service Provider (ISP) and it is needed to allow your Mac to communicate on the network.

Some IP addresses are private and limited to a specific network. Some addresses are public and can be used globally. Other addresses are locked into intranets.

Importantly, for Beyond, only some IP addresses allow incoming and outgoing connections. To act as a server on the Internet, you need an IP address that others can connect to. You need a public IP address.

So how do you know if you have a public IP address? You do not. Not simply anyway.

What is my IP?

You might be thinking that you can easily determine your public IP address. Lots of services exist to tell you your outbound IP address.

This tells you nothing about accepting incoming connections to that address. It also tells you nothing about your non-default routes to the Internet.

Testing Reachability

Beyond actively tests if your Mac is reachable from the Internet. I called this true reachability because your Mac is actively checked for handling both incoming and outgoing traffic.

Reachability verification requires a few steps that involve coordination between your Mac running Beyond, and services I provide to Beyond Members on the Internet. This all happens automatically and requires no technical knowledge. Beyond's beauty is its simplicity of use.

One IP Address? Many!

Beyond first gathers all the IP addresses associated with your Mac's network connections. These include ethernet, wireless, mobile, and any other network connections your Mac may have. Every TCP/IP network connection has at least one IP address associated with it.

Those IP addresses are filtered to remove the known private addresses. Private addresses are reserved by the Internet Engineering Task Force (IETF) for specific uses and should never be used on the global Internet. Beyond also filters out dynamically assigned addresses used for ad-hoc networking.

You can see the gathered addresses in the Beyond Network window of the Beyond application. I suspect many of you will be surprised by how many IP addresses your Mac has.

Gateway Devices

Beyond also searches for Internet Gateway Devices (IGD) on your local network. These are devices that provide either Network Address Translation (NAT) or Universal Plug and Play (UPnP) services.

Internet Gateway Devices are commonly part of your home router or modem. This box connects your Mac to the wider Internet. Many boxes offer a protocol for allowing computers within your local network to accept incoming connections from the global Internet. The two most common protocols are NAT and UPnP. Beyond supports both of these protocols.

If a gateway device is found, Beyond adds its external address to the list of IP addresses to test. It could be the gateway device's address is your true global IP address.

Potential to Proved

With a list of potential IP addresses gathered, Beyond needs help from outside the local network.

Beyond talks to a service provided to Beyond Members. Together they test each potential IP address. The tests determine which IP addresses allow your Mac to serve the Internet.

If both the local Beyond and external service tests pass, then the IP address is shown as verified. Only at this point do you know the address is truly reachable from the global Internet.

What good is a public IP address?

Your Mac can only act as a server to those it can reach. Without a public IP address, any server or service running on your Mac is limited to either the local network or just your computer.

With a public IP address, your Mac can reach the world.

With a verified public IP address, Beyond Members get a domain name.