At home, you add a new system, maybe a Raspberry Pi, or a new VM, or a new home PC. You give it a name. Now you want to network reach that new thing by name. Not IP, by name. So you edit /etc/hosts add an entry and off to the races you go. Oops, wasn’t in sudo mode, let me try that again. There now it works.
But why does this have to be? Why can’t home networking just fucking work with hostnames?
That’s because we are doing it wrong. First you need to get yourself a good router. I have tried a few in the past, failed each time. Then I got an Ubiquiti EdgeRouter 4, and my dreams were answered. You need to get a few settings inside of your router set, then each time a new system comes online and gets an IP from the router, you will be able to hit it by hostname, without needing to configure anything special beyond standard DHCP on each host/VM/thing in your network.
Main Rule: Stop putting 1.1.1.1 or 8.8.8.8 or whatever your favorite public DNS is on every single client, and in every single alternate DNS configuration option in your network. I seen a vSphere VM customization policy wreck havoc on this because it specified 1.1.1.1 as a DNS server and that VM couldn’t ping by name internally. You might think you are helping, but all you are doing is masking something broken upstream. So fucking stop it!
Properly working DNS should delegate and forward your requests upstream where it makes sense. Like if you request something.com and your local router doesn’t have something.com as its domain then it should forward the request upstream. So the only spot you should configure the 1.1.1.1 entry is inside your local DNS server… also known as your router.
Finally your router will need to know which domain, so it can find entries. That domain should also match the default search for DHCP. Once all that is setup, DNS will magically work for you both internal, and external.
So back to making this work on an Ubiquiti EdgeRouter. Do these steps (and nothing more) and things will work. Doing more may not break things now, but in the future you may want to do some more DNS magic and get tripped up.
Set your system domain
In the EdgeOS UI, click on the System tab at the bottom of the screen, then set your System domain-name. This can be anything you really want it to be, though I recommend you spend the $15 and actually buy the name too. I set mine to a funky .house top level domain. Then I went out and bought it.
Setup DHCP domain name
To make sure everything lines up, and your router will actually service your requests when you try to ping by simple hostname we need to have DHCP communicate the domain name properly. To do this, go to the top level Services tab, then the DHCP Server sub tab. From here you should see all the DHCP servers you have configured (1 per interface). On the right side of the screen click Actions, then View Details. Set the domain name here to the same you specified above. Repeat this for each DHCP server.
Set your DNS forwarding servers
Now you likely configured these settings already when you setup your router initially, so we are just going to confirm a few things this time around. On the bottom of the screen, click the System tab. In this screen on the right side you will see a Name Server configuration option. This should only have a single entry, which is your router’s IP. That’s it. Nothing fucking else!
Next we are going to expose one of the small issues with EdgeOS. The fact that they don’t have a graphical way to give you DNS forwarding outside of the tree editor. However before we get to the tree editor, we need to make sure all our interfaces will have forwarding enabled. So go to the top level Services Tab then select the DNS sub tab. From here you should see all your connected interfaces listed. If they are not, add them now. I have 3 interfaces hooked up in my world so it looks like this for me.
Now that we have the interfaces setup for DNS forwarding, we need to tell EdgeOS where to forward the requests. Like I mentioned earlier, you may have already done this when you setup your router, but let’s double check. You need to go to the Config Tree tab, then expand service -> dns -> forwarding. Here you will see the public DNS servers configured. If not, add them as name-servers. You can add more than 1 name-server. This right here, is the only place you configure the public DNS. Don’t do it in your VMs, don’t do it in your vSphere networking policies, don’t do it on your local systems, don’t do it on any other fucking device you have that connects to the internet via this router. Nowhere else!
Now you are setup. You will be able to ping everything by simple hostname, or with the domain name suffix you specified. Any new system or VM that comes online using DHCP to connect will get proper DNS rules and just work. If you need to configure something with a static IP in the client (should not do this), then make sure the only DNS entry is for the router/gateway itself.
Happy home networking by name.