Timeline for Why can't devices on different VLANs, but on the same subnet, communicate?
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Nov 3, 2023 at 14:51 | comment | added | Milind R | @MontyHarder another case, though this is admittedly to paper over another's lacuna. My ISP gives me only one /64 network, but I have dodgy devices that I want to keep on a separate LAN (not VLAN, my router has spare ports). I can either deny my main b devices of IPv6 addresses, or my dodgy devices, or put them both in one subnet while in separate networks. | |
| Apr 12, 2019 at 14:58 | comment | added | Lightness Races in Orbit | And to bring subnets into this to complete the analogy, the wall is effective even when the people are trying to communicate using the same verbal language. | |
| Apr 12, 2019 at 10:17 | comment | added | Matt Douhan | @MontyHarder it’s not common but it happens and then you simply bridge the clans instead of route them | |
| Apr 12, 2019 at 8:50 | comment | added | jcaron | @MontyHarder Actually, it is very common to have the same subnet on many different LANs (and hence VLANs). RFC1918 private addresses are re-used in millions of LANs. You could very well have several separately NATed networks on the same VLAN. This probably happens ad nauseam in hosting environments. But those networks are indeed considered completely independent. | |
| Apr 12, 2019 at 6:32 | comment | added | JFL | @MontyHarder I do have the case: I have interconnections to providers that use the same addressing, and those are made on the same switches. Since I talk to both (via different routers) and they do not talk to each other that is just fine. | |
| Apr 11, 2019 at 19:42 | comment | added | Monty Harder | @Deduplicator I'm not sure why it matters what the source IP of the packet is. How do you know what VLAN an IP is if you're using the same IP range for two or more VLANs? It just doesn't make sense. | |
| Apr 11, 2019 at 19:33 | comment | added | Deduplicator | @MontyHarder Depends. From which network (virtual or not) does it come? | |
| Apr 11, 2019 at 15:58 | comment | added | Monty Harder | I'm hard-pressed to think of any case where using the same subnet on two different VLANs makes sense. Pretend you're a router, and you get a packet destined for 192.168.5.15. Which VLAN is that? | |
| Apr 11, 2019 at 12:57 | history | edited | user36472 | CC BY-SA 4.0 |
added 2 characters in body
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| Apr 11, 2019 at 11:38 | history | answered | JFL | CC BY-SA 4.0 |