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So I just upgraded my ISP, and I went to set up the DMZ for the network. Upon setting the IPv6 DMZ, I ran ipconfig in CMD and this was the output:

Connection-specific DNS Suffix  . : hsd1.or.comcast.net
IPv6 Address. . . . . . . . . . . : 2601:1c0:8802:236::70c7
IPv6 Address. . . . . . . . . . . : 2601:1c0:8802:236:6d29:22a6:b361:9f14
Temporary IPv6 Address. . . . . . : 2601:1c0:8802:236:1188:5bd:ada9:3be6
Link-local IPv6 Address . . . . . : fe80::6d29:22a6:b361:9f14%4
IPv4 Address. . . . . . . . . . . : 192.168.0.234
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : fe80::48f7:c0ff:fe22:1d46%4
                                   192.168.0.1

Now of course I know what most of the stuff on here means, but why do I have 4 IPv6 Addresses for my local machine?

What is the difference between the normal IPv6, Temporary & Link-Local? And why do I have 2 normal local IPv6 addresses / which one do I set for my IPv6 DMZ?

Carter Roeser
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The link-local address is always there, it's a part of how IPv6 works. That address can not be fitted and can only be used to communicate on your local LAN. It's present even when you don't have routable IPv6 from your ISP and it's used to contact your gateway, DHCPv6 server etc.

The first IPv6 address looks pretty short (contains a lot of leading zeroes in the host bit) and my guess would be that it's assigned by a DHCPv6 server.

The second IPv6 address looks more random in the host bits, which is normal for a self-assigned address (SLAAC: stateless address auto configuration). IPv6 hosts will generate their own addresses when the router allows it. Those self-generated addresses used to be based on the MAC address, but more random algorithms are used these days to give a bit more privacy.

The temporary IPv6 address is used for that. While the previous address was generated randomly, it's stable. The temporary address will change over time. It's the default address used for outgoing connections so that for example online services can't identify you by your IPv6 address.

When hosting services you should use one of the two stable IPv6 addresses. Whether you use the DHCPv6 one or the SLAAC one doesn't matter. if you want more predictability you might want to configure the address manually.

Sander Steffann
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See here why multiple IPv6 addresses exist:

https://en.wikipedia.org/wiki/IPv6#Link_local_address

mzhaase
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