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I run native IPv6 at home in San Francisco on Comcast. It just works after some screwing around. Every now and then I'll notice that my web browser selects th

by 2bluesc 13y ago

I run native IPv6 at home in San Francisco on Comcast. It just works after some screwing around. Every now and then I'll notice that my web browser selects the AAAA record for google.com, facebook.com or something else. It'd be nice if they gave out a proper prefix delegation. Instead the best I can get allocated is a /60. Pretty sure the RFC recommends /48's to be allocated to customers.

agwa 13y ago
> It'd be nice if they gave out a proper prefix delegation. Instead the best I can get allocated is a /60. Pretty sure the RFC recommends /48's to be allocated to customers. Out of curiosity, what's your use case for more than 16 subnets? I agree on principle they should give you a /48 if you ask for it, but the truth is that I'm extremely grateful they rethought their original stance, which was that a measly /64 was enough for anyone! That would have been extremely harmful and short-sighted; I feel pretty comfortable with a /60. On that note, does anyone know what Time Warner's maximum prefix delegation size is?
- oofabz 13y ago
  I have been perfectly happy with my /64 for many years. I can't imagine needing multiple subnets for home or small office use.
  - agwa 13y ago
    I think the most compelling use case is a separate guest network (which is firewalled from your normal network; some wireless access points tout this as a feature). Power users might also run a VPN and allocate a subnet to VPN clients. There are also home automation standards that put all your devices on a separate subnet.
  - 2bluesc 13y ago
    I think the single most compelling use case is to segment WiFi and Ethernet traffic. No point in broadcasting useless Ethernet ARPs to the WiFi network when bridged for example.
- simcop2387 13y ago
  I can see use for maybe about 4, not sure about more, but if I recall correctly the privacy extensions require a /48 don't they?
  - agwa 13y ago
    No, the privacy extensions simply use a random interface ID instead of deriving it from the MAC address. You still use a single /64 subnet as usual. (Unless there is an aspect of the privacy extensions I'm not familiar with, but this is what people usually mean when they say "privacy extensions.")
  - zaphoyd 13y ago
    As far as I know the privacy extensions only cycle through the host portion of the address (lower 64 bits) so they should work fine with just a /64. Access to a bigger prefix may help you get around systems that do IP banning in /64 chunks though.
- 2bluesc 13y ago
  I have several subnets (WiFi, LAN, virtual machines, guest WiFi, etc). I don't just bridge WiFi and LAN together like most, I prefer more control. I'll fine with 16 subnets today, but I don't know what'll change in the future. I'm sure I'll have use cases for more.
p1mrx 13y ago
> Every now and then I'll notice that my web browser selects the AAAA record for ... By what method are you noticing that? I made this extension for Chrome that displays a "4" or "6" in the address bar: https://ipvfoo.googlecode.com/ https://ipvfoo.googlecode.com/ Here's a similar extension for Firefox: https://addons.mozilla.org/en-us/firefox/addon/sixornot/ https://addons.mozilla.org/en-us/firefox/addon/sixornot/ Sadly, Hacker News is still stuck on "4".
storborg 13y ago
I just activated a new Comcast connection in Portland. Ironically, IPv6 "just works" totally out of the box, but IPv4 does not.
- zaphoyd 13y ago
  A friend of mine had a similar "issue". He had a modem too new to be on Comcast's approved list so they refused to register it. After plugging it in anyways, IPv4 was filtered to a Comcast captive portal with modem registration instructions but IPv6 stuff worked fine... whoops.
  - p1mrx 13y ago
    Fascinating, does that mean you can plug a random DOCSIS 3.0 modem into any Comcast port, and get free IPv6 access? That's an effective way to encourage deployment, but I'm sure they'll fix the bug if they haven't already :-)
  - wmf 13y ago
    Just like all the places that are only firewalling IPv4 (I blame the iptables/ip6tables split).
- derefr 13y ago
  > Ironically, IPv6 "just works" totally out of the box, but IPv4 does not. Not very ironic at all. IPv6's autoconfiguration (through link-local addresses, the Neighbor-Discovery Protocol, etc.) comes from engineers with decades of experience (and frustration) in managing ISP-sized netblocks.
ianburrell 13y ago
RFC 3177 suggested /48 for customer networks but RFC 6177 allows shorter delegations. /56 and /60 are common allocations for ISPs. /60 should be plenty for residential customer especially if larger allocations are available for business customers.
zurn 13y ago
Wow, sounds pretty incredible that they're giving out substandard prefixes, given the whole point of IPv6... So right from the start, consumer/small business IPv6 gear won't be able to build on having more than a /64 for themselves (to subdelegate for things like home automation networks, virtualization, etc). Oh well, I guess those things will need to support IPv6 NAT!

by 2bluesc 13y ago

agwa 13y ago

> It'd be nice if they gave out a proper prefix delegation. Instead the best I can get allocated is a /60. Pretty sure the RFC recommends /48's to be allocated to customers. Out of curiosity, what's your use case for more than 16 subnets? I agree on principle they should give you a /48 if you ask for it, but the truth is that I'm extremely grateful they rethought their original stance, which was that a measly /64 was enough for anyone! That would have been extremely harmful and short-sighted; I feel pretty comfortable with a /60. On that note, does anyone know what Time Warner's maximum prefix delegation size is?

oofabz 13y ago
I have been perfectly happy with my /64 for many years. I can't imagine needing multiple subnets for home or small office use.
- agwa 13y ago
  I think the most compelling use case is a separate guest network (which is firewalled from your normal network; some wireless access points tout this as a feature). Power users might also run a VPN and allocate a subnet to VPN clients. There are also home automation standards that put all your devices on a separate subnet.
- 2bluesc 13y ago
  I think the single most compelling use case is to segment WiFi and Ethernet traffic. No point in broadcasting useless Ethernet ARPs to the WiFi network when bridged for example.
simcop2387 13y ago
I can see use for maybe about 4, not sure about more, but if I recall correctly the privacy extensions require a /48 don't they?
- agwa 13y ago
  No, the privacy extensions simply use a random interface ID instead of deriving it from the MAC address. You still use a single /64 subnet as usual. (Unless there is an aspect of the privacy extensions I'm not familiar with, but this is what people usually mean when they say "privacy extensions.")
- zaphoyd 13y ago
  As far as I know the privacy extensions only cycle through the host portion of the address (lower 64 bits) so they should work fine with just a /64. Access to a bigger prefix may help you get around systems that do IP banning in /64 chunks though.
2bluesc 13y ago
I have several subnets (WiFi, LAN, virtual machines, guest WiFi, etc). I don't just bridge WiFi and LAN together like most, I prefer more control. I'll fine with 16 subnets today, but I don't know what'll change in the future. I'm sure I'll have use cases for more.

p1mrx 13y ago

> Every now and then I'll notice that my web browser selects the AAAA record for ... By what method are you noticing that? I made this extension for Chrome that displays a "4" or "6" in the address bar: https://ipvfoo.googlecode.com/ https://ipvfoo.googlecode.com/ Here's a similar extension for Firefox: https://addons.mozilla.org/en-us/firefox/addon/sixornot/ https://addons.mozilla.org/en-us/firefox/addon/sixornot/ Sadly, Hacker News is still stuck on "4".

storborg 13y ago

I just activated a new Comcast connection in Portland. Ironically, IPv6 "just works" totally out of the box, but IPv4 does not.

zaphoyd 13y ago
A friend of mine had a similar "issue". He had a modem too new to be on Comcast's approved list so they refused to register it. After plugging it in anyways, IPv4 was filtered to a Comcast captive portal with modem registration instructions but IPv6 stuff worked fine... whoops.
- p1mrx 13y ago
  Fascinating, does that mean you can plug a random DOCSIS 3.0 modem into any Comcast port, and get free IPv6 access? That's an effective way to encourage deployment, but I'm sure they'll fix the bug if they haven't already :-)
- wmf 13y ago
  Just like all the places that are only firewalling IPv4 (I blame the iptables/ip6tables split).
derefr 13y ago
> Ironically, IPv6 "just works" totally out of the box, but IPv4 does not. Not very ironic at all. IPv6's autoconfiguration (through link-local addresses, the Neighbor-Discovery Protocol, etc.) comes from engineers with decades of experience (and frustration) in managing ISP-sized netblocks.

ianburrell 13y ago

RFC 3177 suggested /48 for customer networks but RFC 6177 allows shorter delegations. /56 and /60 are common allocations for ISPs. /60 should be plenty for residential customer especially if larger allocations are available for business customers.

zurn 13y ago

Wow, sounds pretty incredible that they're giving out substandard prefixes, given the whole point of IPv6... So right from the start, consumer/small business IPv6 gear won't be able to build on having more than a /64 for themselves (to subdelegate for things like home automation networks, virtualization, etc). Oh well, I guess those things will need to support IPv6 NAT!