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In an otherwise fully IPv6 enabled network, can devices put behind Araknis switches use IPv6? I can't find any mention of IPv6 here: https://www.snapav.com/shop/en/snapav/araknis-switches

Araknis's only current router does support IPv6 (see Specs): https://www.snapav.com/shop/en/snapav/routers/araknis-networks-reg%3B-300-series-dual-wan-gigabit-vpn-router-an-300-rt-4l2w

I'm confused why they'd sell IPv6 routers but not IPv6 switches.

Context: I'm staying at a house with an Araknis router and separate Araknis switch. The router seems to support IPv6 according to its web interface but I can't physically access it to test plugging a device directly into it. But everything behind the switch doesn't seem to pick up an IPv6 address. On SnapAV's website, they don't mention IPv6 support on any of their switches, but their latest routers support IPv6 (mentioned in Specs section).

Update: Thanks for the answers everyone. The router was getting a public IPv6 from the ISP. I got access to the equipment and plugged a device directly into the router rather than the switch, and now it's getting an IPv6 address (though only a fc00::... unique-local address until I enabled prefix delegation on the router, after which it got an additional global address). So, it seems the switch is somehow the problem, despite the theory that it should be ignorant of IPv4 and IPv6. The switch that isn't working for me is an AN-100-SW-R-16 ("Araknis Networks® 100 Series Unmanaged Gigabit Switch with Rear Ports")

Alexander Taylor
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  • Just cos the router supports v6 doesn't mean the Service Provider does. You could test by using two devices on the LAN and ping their link-local addresses (the fe80::1234:1234:1234:1234 address) – Criggie Jan 02 '18 at 02:20
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    It can't be the switch if it is a layer-2 switch. More likely, it is the configuration of the router interface to which the switch is connected. Lyer-2 switches know nothing about layer-3 protocols, and they carry any layer-3 protocols. – Ron Maupin Jan 02 '18 at 07:21
  • fc00::/8 is reserved for future use. Any network using that range today is misconfigured. And the added information that the switch is supposed to be unmanaged just reinforces that it should have no concept of what IP even is. Did you verify that your problem isn't due to the ports on the router being configured differently? – kasperd Jan 02 '18 at 09:50
  • This is strange indeed. The only port-specific settings are speed and duplex. (I've been pouring over these settings.) Btw I've emailed support@araknisnetworks.com and will report back when I hear from them. – Alexander Taylor Jan 02 '18 at 19:47
  • How did you enable prefix delegation? I’m trying to enable PD on an Araknis 300 router, but can’t find any option for it. – Michael Donohue Jul 10 '19 at 06:03

2 Answers2

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A switch doesn't know about IP.

Switches forward Ethernet frames. They don't need to know anything about the protocols at higher layers.

If it is a managed switch it may have a web interface used to configure the switch over IP. Such an interface could support IPv4 or IPv6 or both. However which IP protocol you use to configure the switch doesn't influence what protocols you can use through the switch. You can even send non-IP protocols through a switch.

A managed switch may also have features going beyond switching, some of those features may operate on the IP layer. Some products take this so far that they are actually fully capable routers. Whether a specific device is acting as a switch or a router can depend on how it is configured.

The lack of IPv6 access for hosts connected to the network is unlikely to be caused by the switches, it is more likely caused by the router or the ISP not supporting IPv6.

kasperd
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    A *real* switch doesn't know about IP. Careful readers should note that some manufacturers sell combined switch/router devices advertised as one or the other even though they perform both functions. This is annoying and misleading, but it happens. – Kevin Jan 02 '18 at 01:39
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    In particular, manufacturers like to call "very fast" routers "switches" in order to emphasize that they are "very fast". (For various definitions of "very fast".) – Jörg W Mittag Jan 02 '18 at 02:19
  • @Kevin You are right. I intended to mention that but somehow forgot. I have added a paragraph mentioning that possibility. – kasperd Jan 02 '18 at 09:37
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    @JörgWMittag Yeah isn't it weird how a device with routing done entirely in software running on a general purpose CPU is sold as a router but a device with routing done in hardware is sold as a switch? – kasperd Jan 02 '18 at 09:41
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    @kasperd for extra fun, the one that's sold as a router probably has a hardware switch in it. – hobbs Jan 02 '18 at 21:26
  • Also, some switches require `IPv6 unicast forwarding` to pass traffic... Which is insane – Jacob Evans Jan 02 '18 at 21:46
  • There also are layer 3 switches. Some of them may actually be routers, but some really are switches that use IP addresses instead of MAC addresses to identify the destination port. The difference between a switch and a router is that routers connect *different* networks (i.e., subnets), while all ports on a switch are in the same network. At least until VLANs come into play... – Kevin Keane Jan 03 '18 at 05:42
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The link provided suggests that there are three levels of software switching: unmanaged, Web-based L2 and managed L2. The common point to all of these options is that the device doesn't support routing.

So - what this means is that any of these switches are going to happily pass frames, whether IPv6, IPv4 or IPX (just picking out a random non-IP example). What these switches won't do is route between different subnets (i.e. the switch won't act as the gateway for the subnet).

If you happen to connect an IPv6-enabled router (...to include the Araknis example you've mentioned) then it will be able to communicate with hosts on the L2-only switch to provide connectivity between subnets (..or to the greater Internet, if so equipped).

If v6 isn't working at your location I'd suggest focusing on the router configuration to see that there's both upstream connectivity and appropriate configuration on the interfaces. After this the question becomes proper support for RA, routing to the upstream, etc.

rnxrx
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  • Kind-of-exception to "happily pass frames": Tagged VLAN or Jumbo frames can give surprises with unmanaged switches unaware of such frame types and their extra length, or default configuration of managed switches... but that is still all L2 stuff.... – rackandboneman Jan 02 '18 at 14:34