ZeroTier and DNS

scottalanmiller

I have internal DNS for the same FQDN space and a separate DNS on the internet.

Yup, that is Split Horizon.

Although I could see why that would be mistaken as a failure condition.

scottalanmiller

What is the purpose in your split horizon? Why are you serving out something to the public from your internal DNS servers?

Dashrender

Here is Microsoft calling it Split Brain.
http://blogs.technet.com/b/networking/archive/2015/05/12/split-brain-dns-deployment-using-windows-dns-server-policies.aspx

scottalanmiller

Very weird. I guess they are either just confused or they are trying to make a point that it is a failure condition that should be avoided.

Dashrender

If you do a google search for split brain DNS, you come up with many people using the term to describe this setup.

scottalanmiller

@Dashrender said:

If you do a google search for split brain DNS, you come up with many people using the term to describe this setup.

If you Google cloud you get a lot of peoples saying a lot of things

Dashrender

@scottalanmiller said:

@Dashrender said:

If you do a google search for split brain DNS, you come up with many people using the term to describe this setup.

If you Google cloud you get a lot of peoples saying a lot of things

Touche!

scottalanmiller

So what is the reason for the split horizon? What external entities are getting DNS resolution from your internal DNS servers?

Dashrender

@scottalanmiller said:

So what is the reason for the split horizon? What external entities are getting DNS resolution from your internal DNS servers?

Other than remote users, non.

We have the same domainname inhouse for AD as we use for our website on the interwebs...
Very little overlap, but email would be one of those overlaps.
Externally points to our ISP provided IP, internally, of course inside IP.

scottalanmiller

@Dashrender said:

Other than remote users, non.

Why would remote users get different DNS responses?

scottalanmiller

@Dashrender said:

Very little overlap, but email would be one of those overlaps.

How is email affected?

scottalanmiller

@Dashrender said:

Externally points to our ISP provided IP, internally, of course inside IP.

Only for the website, of course, not email. Why not have external uses see the website internally?

scottalanmiller

Good point, let's start a new topic on Split Horizon DNS. When to use it and if it makes sense in your case