The Official Computer Tech Support Thread

Freebase Dali · 10-08-2018, 06:01 PM

Quote:

Originally Posted by Stephen

Under my DNS Servers in OSX I Have one listed that looks like hexadecimal separated by colons with the first set separated by two colons. Is this a valid format for a DNS server?

ie.

nnnn::nnnn:nnnn:nnnn:nnnn

That seems like an IPV6 address. Basically it's the successor to IPV4. Version 6 gives you a lot more addressing possibilities because it's 128 bits rather than 32.
The two colons just means that zeros were omitted. It's called Zero Compression (can only occur once in an address) and it's used to simplify the address while still meaning the same thing in binary. In your example, I can see that 3 successive sets of hex were all zeros, so your example could have looked like this in reality:

nnnn:0000:0000:0000:nnnn:nnnn:nnnn:nnnn

The compression of zeros makes the address less verbose, as the Zero Compression can imply what's in those three groups by looking at the remaining number of groups and knowing only one Zero Compression can occur in the address, given that there will always be 8 groups of hex.

As to whether the particular IPV6 address is valid for a DNS server, that depends on two things:

1. Is the DNS server it's referencing assigned the IPV6 address and listening to requests on it?
2. Can your computer communicate via IPV6 to receive a response from the DNS server with an IPV6 address?

You can find that out by performing a ping from the client, using the IPV6 address. If it responds, then it's just as valid as an IPV4 address. The DNS protocol itself is irrelevant of that.

IPV6 still isn't ubiquitous as we have a lot of IPV4 addresses out there, but I've noticed over the past few years that some ISPs are beginning to assign IPV6 addresses to routers, and depending on your router and its configuration, it may be doing the same for the auto configuration of devices within the network, which would be relevant if you're not statically setting your own DNS servers on your network card with something like Google's 8.8.8.8, etc.