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DHCPv6-PD – First Steps

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Re: DHCPv6-PD – First Steps

#11

Post by hamandcheese »

kiwijamo wrote: post #10
j16sdiz wrote: post #8

Earlier quoted context omitted.

I meant.... I love DHCPv6. If only RA wasn't mandatory part of IPv6, I am all for DHCPv6. It's the fault of early IPv6 designers with NIH syndrome created this mess.

Out of interest as I have found IPv6 RA to work flawlessly for my home network (alongside legacy IPv4 DHCP), what advantage (if any) is there in deploying DHCPv6 within the home LAN? Or were you meaning to say DHCPv6 is great for certain (enterprise?) use cases?

When I was experimenting with IPv6 on my lan, router advertisements indeed worked great!

But the big loss was that I had no control to reserve a particular IPv6 address for a particular MAC address inside the DHCP server, or assign DNS names automatically, etc. since it's basically 1 way - device receives a RA then configures itself with a random address.

Re: DHCPv6-PD – First Steps

#12

Post by hamandcheese »

miller_joe wrote: post #5

This is great! I’ve been using ipv6 on openbsd for a while now, starting with a hurricane electric tunnel years ago then to native v6 on Comcast and now Sonic. Configuring ipv6 PD has not been supported in base this whole time. I recall using wide-dhcp6c years ago and then switching to the dhcpcd in the article. The situation has improved, slowly, but it will be great to have this in the base system *EDIT*: dhcp6leas…

Did Sonic start offering native IPv6? Last I looked, it was only covered via tunnel only.

Re: DHCPv6-PD – First Steps

#13

Post by [deleted] »

hamandcheese wrote: post #11
kiwijamo wrote: post #10

Earlier quoted context omitted.

Out of interest as I have found IPv6 RA to work flawlessly for my home network (alongside legacy IPv4 DHCP), what advantage (if any) is there in deploying DHCPv6 within the home LAN? Or were you meaning to say DHCPv6 is great for certain (enterprise?) use cases?

When I was experimenting with IPv6 on my lan, router advertisements indeed worked great! But the big loss was that I had no control to reserve a particular IPv6 address for a particular MAC address inside the DHCP server, or assign DNS names automatically, etc. since it's basically 1 way - device receives a RA then configures itself with a random address.

[deleted]

Re: DHCPv6-PD – First Steps

#14

Post by Spivak »

j16sdiz wrote: post #8
j16sdiz wrote: post #7

Earlier quoted context omitted.

No. In IPv6, you can get an address using RA. DHCPv6 only if you want to smuggle some unrelated metadata as options (which, of course, not widely used outside enterprise). DHCPv6-PD are used only when you need a whole prefix. If everybody implement all the specs out there, we will have two different DNS record type, 4 or 5 address allocation schemes, a handful of IPv6-over-IPv4 protocol, whole a lots of incomplete an…

I meant.... I love DHCPv6. If only RA wasn't mandatory part of IPv6, I am all for DHCPv6. It's the fault of early IPv6 designers with NIH syndrome created this mess.

And also really optimistic that client-client connections are allowed to perform the auto-configuration.

Probably true in a home network, probably not at the office. I hope not at the office.

Re: DHCPv6-PD – First Steps

#15

Post by 38 »

candiddevmike wrote: post #2

While the article is focused on OpenBSD, implementing DHCPv6 with systemd-networkd is really slick and typically a 1-2 line config for your interfaces: Upstream: [DHCPv6] PrefixDelegationHint=::/56 Downstream: [DHCPv6PrefixDelegation] Token=::1

[flagged]

Re: DHCPv6-PD – First Steps

#16

Post by Tigress8780 »

j16sdiz wrote: post #7
bastard_op wrote: post #6

"3 Because of android refusing to implement it." So, some interesting history for the not-network-engineers out there on ipv6 fun. https://issuetracker.google.com/issues/36949085 Why do people hate ipv6? Google comes to mind as one place to start.

No. In IPv6, you can get an address using RA. DHCPv6 only if you want to smuggle some unrelated metadata as options (which, of course, not widely used outside enterprise). DHCPv6-PD are used only when you need a whole prefix. If everybody implement all the specs out there, we will have two different DNS record type, 4 or 5 address allocation schemes, a handful of IPv6-over-IPv4 protocol, whole a lots of incomplete an…

SLAAC is fine, until you somehow get a subnet smaller than /64 on your router, in which case SLAAC completely breaks. I understand why SLAAC has such a limitation, but this is what we get.

It's not optimal, but the upstream network provider does not budge, and now everything except Android devices get IPv6 address via DHCPv6.

Re: DHCPv6-PD – First Steps

#17

Post by Dylan16807 »

Tigress8780 wrote: post #16
j16sdiz wrote: post #7

Earlier quoted context omitted.

No. In IPv6, you can get an address using RA. DHCPv6 only if you want to smuggle some unrelated metadata as options (which, of course, not widely used outside enterprise). DHCPv6-PD are used only when you need a whole prefix. If everybody implement all the specs out there, we will have two different DNS record type, 4 or 5 address allocation schemes, a handful of IPv6-over-IPv4 protocol, whole a lots of incomplete an…

SLAAC is fine, until you somehow get a subnet smaller than /64 on your router, in which case SLAAC completely breaks. I understand why SLAAC has such a limitation, but this is what we get. It's not optimal, but the upstream network provider does not budge, and now everything except Android devices get IPv6 address via DHCPv6.

Who's out there being so crazily stingy? Allocating a subnet that small is making things more complicated for no benefit.

Re: DHCPv6-PD – First Steps

#18

Post by mathsmath »

Dylan16807 wrote: post #17
Tigress8780 wrote: post #16

Earlier quoted context omitted.

SLAAC is fine, until you somehow get a subnet smaller than /64 on your router, in which case SLAAC completely breaks. I understand why SLAAC has such a limitation, but this is what we get. It's not optimal, but the upstream network provider does not budge, and now everything except Android devices get IPv6 address via DHCPv6.

Who's out there being so crazily stingy? Allocating a subnet that small is making things more complicated for no benefit.

Someone should double check me, but I think PD less than a /64 also just breaks (and probably is against the spec).

A lot of the complaints I have seen in the last decade is from ISPs doing silly things and cutting their teeth on fresh IPv6 deployments. My ISP seems to have their collective ducks in a row now, and it has been rock solid for years.

I actually had a case recently where a misbehaving IPv4 IoT device consumed my entire DHCP pool. IPv6 devices kept chugging along without any problem.

Re: DHCPv6-PD – First Steps

#19

Post by mathsmath »

miller_joe wrote: post #5

This is great! I’ve been using ipv6 on openbsd for a while now, starting with a hurricane electric tunnel years ago then to native v6 on Comcast and now Sonic. Configuring ipv6 PD has not been supported in base this whole time. I recall using wide-dhcp6c years ago and then switching to the dhcpcd in the article. The situation has improved, slowly, but it will be great to have this in the base system *EDIT*: dhcp6leas…

[dead]

Re: DHCPv6-PD – First Steps

#20

Post by bastard_op »

wmf wrote: post #9
bastard_op wrote: post #6

"3 Because of android refusing to implement it." So, some interesting history for the not-network-engineers out there on ipv6 fun. https://issuetracker.google.com/issues/36949085 Why do people hate ipv6? Google comes to mind as one place to start.

Google doesn't hate IPv6; they've put huge effort into it. This particular issue is just weird.

Weird indeed. It's sort of fun to see updates as you still get some random personal lashing out at one member in particular for a feud no one remembers but them, but either way it's like... why this mess we still can't have dhcpv6 on android for enterprise?
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