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> I've been toying with the idea of putting one in a dedicated VLAN with the WAN port of my router, with another ethernet cable connecting to the LAN port. Tha

> I've been toying with the idea of putting one in a dedicated VLAN with the WAN port of my router, with another ethernet cable connecting to the LAN port. That's what I'd like to do, but I haven't bothered to get a bi-directional SFP for my switch. Soon... > I might also get away with using only one ethernet port ... I would definitely avoid that at all costs! Exposing your internal network to your ISP's network is a really bad idea. With a managed switch, you'll want to disable as much of the "link-local" and other layer 2 "noise" as you can (e.g., CDP, LLDP, STP, etc.). You may need to enable 802.1Q on your upstream-facing switchport anyways (and configure VLAN IDs, of course), but this would depend on your ISP's configuration. Either way, I'd still use a separate physical cable (between the router and switch) just for the "LAN side" -- if you weigh the pros and cons, it's a no-brainer!

baybal2 6y ago
> I would definitely avoid that at all costs! Exposing your internal network to your ISP's network is a really bad idea. I have yet to see a single ISP that doesn't do it on their own side.
MayeulC 6y ago
Hmm, I think it would not necessarily expose the rest of the network, though: if the router supports it, I would use a tagged vlan (let's say wan.42) as the upstream connection, and wan.10 as a lan port, part of the switched interfaces. On the switch side, I'd have put the SFP connector inside VLAN 42, untagged, and put every other port in VLAN 10, untagged. There are probably a couple other ways to achieve this, and ISPs sometimes use tagged VLANs as well. But I think that could work (I have little experience with VLANs, so I might be wrong, feel free to point it out to me). On the other hand, if I had gigabit fiber, a single cable would halve my bandwidth. And I'd pick the multiple cable option over the other as long as I can afford it (enough ports)! Thanks for pointing out the layer 2 "noise". I wonder if my switch wouldn't support bridging together two ports, I think it runs Linux...

baybal2 6y ago

> I would definitely avoid that at all costs! Exposing your internal network to your ISP's network is a really bad idea. I have yet to see a single ISP that doesn't do it on their own side.

MayeulC 6y ago

Hmm, I think it would not necessarily expose the rest of the network, though: if the router supports it, I would use a tagged vlan (let's say wan.42) as the upstream connection, and wan.10 as a lan port, part of the switched interfaces. On the switch side, I'd have put the SFP connector inside VLAN 42, untagged, and put every other port in VLAN 10, untagged. There are probably a couple other ways to achieve this, and ISPs sometimes use tagged VLANs as well. But I think that could work (I have little experience with VLANs, so I might be wrong, feel free to point it out to me). On the other hand, if I had gigabit fiber, a single cable would halve my bandwidth. And I'd pick the multiple cable option over the other as long as I can afford it (enough ports)! Thanks for pointing out the layer 2 "noise". I wonder if my switch wouldn't support bridging together two ports, I think it runs Linux...