6 ms·

Everything should get its IPv6 configuration via SLAAC. DHCPv6 is only useful when you plan to provide prefix delegation for extra routers or network boot infor

Everything should get its IPv6 configuration via SLAAC. DHCPv6 is only useful when you plan to provide prefix delegation for extra routers or network boot information.

stevefan1999 4y ago
just a funny joke: what about using IBGP/OSPF for prefix delegation?
- justin_oaks 4y ago
  How does that work you have more than one ISP giving you an IPv6 prefix?
  - justin_oaks 4y ago
    Oops. Meant to reply to parent. Now I can't delete the comment.
tjoff 4y ago
So how do you do DNS then? Not sure if this is a good source but it had some history to recap, and it doesn't look pretty... https://www.reddit.com/r/networking/comments/ajb2ec/comment/eex3d2c/?utm_source=reddit&utm_medium=web2x&context=3 https://www.reddit.com/r/networking/comments/ajb2ec/comment/... [...] To be honest because of this hot mess if you want to reliably support any possible client you'll need to do both DHCPv6 and RDNSS for DNS information. [...]
- porbelm 4y ago
  The SLAAC should not change after the host has generated it during installation / first connection, as long as you don't reinstall the OS etc. It's basically no problem. Even better: I can set my own ::/64 so personal servers at home can be ::d3ad:b33f and accessible from outside without NAT. It's beautiful. Firewall configuration is not hard either these days is it?
  - tjoff 4y ago
    So I have to manually configure every device to be able to use internet? Every friends phone that wants to connect to my wifi needs manual setup? That is a problem. To which the solution is IPv4?
    - yesco 4y ago
      Why do you think this? What led you to assuming these things? You would only need to configure any of this if you want to allow external connections, which isn't much different than setting up port forwarding with IPv4 + NAT, except with IPv6 it's less complicated.
      - tjoff 4y ago
        Literally the post I answered. Fact: SLAAC does not do DNS. So, my question then is: how do you do DNS? Answer: "The SLAAC should not change after the host has generated it during installation / first connection, as long as you don't reinstall the OS etc." Since SLAAC does not do DNS that answer implies that you'd enter it during connection/installation to complete the config.
        jeroenhd 4y ago
        SLAAC installations can use RDNSS to configure DNS. Windows, according to Wikipedia, doesn't support it, but if you want to please Microsoft there's stateless DHCPv6 (which does not maintain leases, configure addresses, or do anything else that SLAAC doesn't do already; it can be simple piece of software in comparison). On the other hand, Android and ChromeOS don't support DHCPv6 for DNS server provisioning because of Google's opinion about all matters related to DHCPv6. A pain, but not impossible to overcome either. As for unchanging addresses, SLAAC is bound to the device MAC address so a reinstall should give you the same IP. However, you are/should be running privacy extensions, which means your outgoing IP will rotate to prevent tracking (as your IP is based on your MAC address and using that would make tracking way too easy). You'll still have the same primary IP, though, unless you add a second device to the network with the same MAC address.
- staringback 4y ago
  IPv6 router advertisement.
- tjohns 4y ago
  SLAAC can configure DNS automatically (via RDNSS). Or you can run DHCPv6 just to hand out DNS settings (or anything else you want more control over), even if it's not handling addressing. But this isn't necessary for small deployments. Personally, I've never had any problems with pure SLAAC (no DHCPv6) on my home network.
- labcomputer 4y ago
  That source is, at best, dated. Sending DNS info is one of the options in SLAAC (just like how it is an option for DHCPv4). You just configure your router to advertise DNS servers via SLAAC Router Advertisements (RAs) the same way you would via DHCP. One of the benefits is that any configuration changes propagate almost immediately—you don’t have to wait for DHCP clients to renew their lease to get new DNS servers. Also, you can (if you want) have the DNS server advertise itself using the same mechanism. The only common clients that can’t use SLAAC-based DNS configuration are older (unsupported) versions of windows. Even then, setting up DHCPv6 (in unmanaged mode) to send DNS servers is easy.
pantalaimon 4y ago
You can even do prefix delegation with SLAAC, although not really in a standard way https://doc.riot-os.org/group__net__gnrc__ipv6__auto__subnets.html https://doc.riot-os.org/group__net__gnrc__ipv6__auto__subnet...
justin_oaks 4y ago
How does that work you have more than one ISP giving you an IPv6 prefix?

Everything should get its IPv6 configuration via SLAAC. DHCPv6 is only useful when you plan to provide prefix delegation for extra routers or network boot information.

stevefan1999 4y ago

just a funny joke: what about using IBGP/OSPF for prefix delegation?

justin_oaks 4y ago
How does that work you have more than one ISP giving you an IPv6 prefix?
- justin_oaks 4y ago
  Oops. Meant to reply to parent. Now I can't delete the comment.

tjoff 4y ago

So how do you do DNS then? Not sure if this is a good source but it had some history to recap, and it doesn't look pretty... https://www.reddit.com/r/networking/comments/ajb2ec/comment/eex3d2c/?utm_source=reddit&utm_medium=web2x&context=3 https://www.reddit.com/r/networking/comments/ajb2ec/comment/... [...] To be honest because of this hot mess if you want to reliably support any possible client you'll need to do both DHCPv6 and RDNSS for DNS information. [...]

porbelm 4y ago
The SLAAC should not change after the host has generated it during installation / first connection, as long as you don't reinstall the OS etc. It's basically no problem. Even better: I can set my own ::/64 so personal servers at home can be ::d3ad:b33f and accessible from outside without NAT. It's beautiful. Firewall configuration is not hard either these days is it?
- tjoff 4y ago
  So I have to manually configure every device to be able to use internet? Every friends phone that wants to connect to my wifi needs manual setup? That is a problem. To which the solution is IPv4?
  - yesco 4y ago
    Why do you think this? What led you to assuming these things? You would only need to configure any of this if you want to allow external connections, which isn't much different than setting up port forwarding with IPv4 + NAT, except with IPv6 it's less complicated.
    - tjoff 4y ago
      Literally the post I answered. Fact: SLAAC does not do DNS. So, my question then is: how do you do DNS? Answer: "The SLAAC should not change after the host has generated it during installation / first connection, as long as you don't reinstall the OS etc." Since SLAAC does not do DNS that answer implies that you'd enter it during connection/installation to complete the config.
      - jeroenhd 4y ago
        SLAAC installations can use RDNSS to configure DNS. Windows, according to Wikipedia, doesn't support it, but if you want to please Microsoft there's stateless DHCPv6 (which does not maintain leases, configure addresses, or do anything else that SLAAC doesn't do already; it can be simple piece of software in comparison). On the other hand, Android and ChromeOS don't support DHCPv6 for DNS server provisioning because of Google's opinion about all matters related to DHCPv6. A pain, but not impossible to overcome either. As for unchanging addresses, SLAAC is bound to the device MAC address so a reinstall should give you the same IP. However, you are/should be running privacy extensions, which means your outgoing IP will rotate to prevent tracking (as your IP is based on your MAC address and using that would make tracking way too easy). You'll still have the same primary IP, though, unless you add a second device to the network with the same MAC address.
staringback 4y ago
IPv6 router advertisement.
tjohns 4y ago
SLAAC can configure DNS automatically (via RDNSS). Or you can run DHCPv6 just to hand out DNS settings (or anything else you want more control over), even if it's not handling addressing. But this isn't necessary for small deployments. Personally, I've never had any problems with pure SLAAC (no DHCPv6) on my home network.
labcomputer 4y ago
That source is, at best, dated. Sending DNS info is one of the options in SLAAC (just like how it is an option for DHCPv4). You just configure your router to advertise DNS servers via SLAAC Router Advertisements (RAs) the same way you would via DHCP. One of the benefits is that any configuration changes propagate almost immediately—you don’t have to wait for DHCP clients to renew their lease to get new DNS servers. Also, you can (if you want) have the DNS server advertise itself using the same mechanism. The only common clients that can’t use SLAAC-based DNS configuration are older (unsupported) versions of windows. Even then, setting up DHCPv6 (in unmanaged mode) to send DNS servers is easy.

pantalaimon 4y ago

You can even do prefix delegation with SLAAC, although not really in a standard way https://doc.riot-os.org/group__net__gnrc__ipv6__auto__subnets.html https://doc.riot-os.org/group__net__gnrc__ipv6__auto__subnet...

justin_oaks 4y ago

How does that work you have more than one ISP giving you an IPv6 prefix?