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Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

vladimir.varank.in

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Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#21

Post by amaccuish »

eqvinox wrote: post #18

The post isn't mentioning DHCPv6-PD[*] (prefix delegation.) I feel like murphy's law is kicking into effect right now and the ISP-provided router actually supports PD to give downstream routers their own /64. (Or maybe not. Who knows. I feel like the post would've mentioned PD if they tried it.) Also: I divided it into a smaller subnet 2001:db8:abc:123:40::/76 Anything on a broadcast/multinode segment that isn't /64…

Upvoting as good idea, but most routers I know, evening running custom firmware, don't support delegating a wan prefix on request from lan side.

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#22

Post by amaccuish »

eqvinox wrote: post #20
amaccuish wrote: post #17

Out of interest, why didn't you just bridge the two interfaces? Did you want everything on a separate subnet? (maybe I missed that but but you mentioned before how everything used to be directly plugged in anyway)

You can't bridge regular 802.11 wireless into ethernet at the client side. The on-air addressing requires the client MAC address to be the same as the ethernet packet's sender. 802.11 has the concept of "transmitter address" and "receiver address" in addition to source and destination. Those are MAC addresses too, but they're relevant for the on-air radio management. Things like RTS, CTS, ACKs, and fancier things lik…

How did my AirPort Express or do my Sonos do it? Just rewrite the MAC Address? (is that then not technically bridging from terminology pov?)

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#23

Post by astrange »

zrail wrote: post #4
sneak wrote: post #2

This seems like a lot of work to avoid having to run a long cable.

> This seems like a lot of work I see this is your first introduction to the homelab hobby. Welcome!

I tried to figure out what a homelab was once, but it seemed to just be people who enjoyed having a lot of fan noise at home so they could assemble VLANs for no particular reason.

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#24

Post by eqvinox »

amaccuish wrote: post #22
eqvinox wrote: post #20

Earlier quoted context omitted.

You can't bridge regular 802.11 wireless into ethernet at the client side. The on-air addressing requires the client MAC address to be the same as the ethernet packet's sender. 802.11 has the concept of "transmitter address" and "receiver address" in addition to source and destination. Those are MAC addresses too, but they're relevant for the on-air radio management. Things like RTS, CTS, ACKs, and fancier things lik…

How did my AirPort Express or do my Sonos do it? Just rewrite the MAC Address? (is that then not technically bridging from terminology pov?)

Yes, one of the worst hacks in all of home networking is exactly this... rewriting the MAC address. aka "MAC NAT." Alternatively, proxy ARP + proxy ND can also work. The Apple stuff may be able to autonegotiate over some proprietary handshake if it's an Apple AP and Apple Extender.

There is also a new standard that covers 4-address frames, 802.11ak; I have no idea how widely that is adopted though — it was only released in 2018[1].

[1] https://standards.ieee.org/news/2018/ieee_802_11ak-2018.html

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#25

Post by zrail »

astrange wrote: post #23
zrail wrote: post #4

Earlier quoted context omitted.

> This seems like a lot of work I see this is your first introduction to the homelab hobby. Welcome!

I tried to figure out what a homelab was once, but it seemed to just be people who enjoyed having a lot of fan noise at home so they could assemble VLANs for no particular reason.

Homelab is a wide hobby. Some people assemble their lab to learn how things work as a way to skill up for work. Some people assemble a small lab (sometimes just a single box with a bunch of VMs) to run home automation or media applications.

Other people just enjoy the blinkenlights.

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#26

Post by eqvinox »

amaccuish wrote: post #21
eqvinox wrote: post #18

The post isn't mentioning DHCPv6-PD[*] (prefix delegation.) I feel like murphy's law is kicking into effect right now and the ISP-provided router actually supports PD to give downstream routers their own /64. (Or maybe not. Who knows. I feel like the post would've mentioned PD if they tried it.) Also: I divided it into a smaller subnet 2001:db8:abc:123:40::/76 Anything on a broadcast/multinode segment that isn't /64…

Upvoting as good idea, but most routers I know, evening running custom firmware, don't support delegating a wan prefix on request from lan side.

Really depends on the ISP; it's actually on the certification mandatory feature list for some network operators. (Comcast, AFAIK.) But yeah, no way to tell if the particular device and setup the author has supports it.

(But it should be a very early thing to try, if it's available everything else becomes much easier.)

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#27

Post by amaccuish »

eqvinox wrote: post #24
amaccuish wrote: post #22

Earlier quoted context omitted.

How did my AirPort Express or do my Sonos do it? Just rewrite the MAC Address? (is that then not technically bridging from terminology pov?)

Yes, one of the worst hacks in all of home networking is exactly this... rewriting the MAC address. aka "MAC NAT." Alternatively, proxy ARP + proxy ND can also work. The Apple stuff may be able to autonegotiate over some proprietary handshake if it's an Apple AP and Apple Extender. There is also a new standard that covers 4-address frames, 802.11ak; I have no idea how widely that is adopted though — it was only relea…

Thank you for your expertise! Out of interest, why is it a hack? Does it break things elsewhere? Why is it better to do it at the IP level?

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#28

Post by MayeulC »

mbreese wrote: post #10
sneak wrote: post #5

Earlier quoted context omitted.

I have 200TB in my garage.

To be fair, physically moving a small cluster of RPis around is a bit easier than moving 200TB. So a wireless linkup isn't that strange of a setup.

Well, to be pedantic, physically moving 200 TB around shouldn't be really hard, if it's on 10 TB drives...

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#29

Post by [deleted] »

eqvinox wrote: post #26
amaccuish wrote: post #21

Earlier quoted context omitted.

Upvoting as good idea, but most routers I know, evening running custom firmware, don't support delegating a wan prefix on request from lan side.

Really depends on the ISP; it's actually on the certification mandatory feature list for some network operators. (Comcast, AFAIK.) But yeah, no way to tell if the particular device and setup the author has supports it. (But it should be a very early thing to try, if it's available everything else becomes much easier.)

[deleted]

Re: Wireless-to-Ethernet island for RPi cluster: IPv6, NDP proxy, mDNS reflector

#30

Post by Arnavion »

amaccuish wrote: post #21
eqvinox wrote: post #18

The post isn't mentioning DHCPv6-PD[*] (prefix delegation.) I feel like murphy's law is kicking into effect right now and the ISP-provided router actually supports PD to give downstream routers their own /64. (Or maybe not. Who knows. I feel like the post would've mentioned PD if they tried it.) Also: I divided it into a smaller subnet 2001:db8:abc:123:40::/76 Anything on a broadcast/multinode segment that isn't /64…

Upvoting as good idea, but most routers I know, evening running custom firmware, don't support delegating a wan prefix on request from lan side.

I don't know about *WRT and Tomato, but OPNsense / pfSense and OpenBSD definitely support PD.
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