Usually you would configure that on the switch
Comment on Basic networking/subnetting question.
marauding_gibberish142@lemmy.dbzer0.com 1 week agoThank you. In theory, is there a mechanism which will prevent other hosts from tagging the interface with a VLAN ID common with another host and spoof traffic that way? Sorry, I need to study more about this stuff
possiblylinux127@lemmy.zip 1 week ago
marauding_gibberish142@lemmy.dbzer0.com 1 week ago
I see, I was completely off-track lol. But isn’t this really for a setup where each computer is connected to an individual port of the switch? I.E. this won’t work if to one port of an L3 switch one were to attach a dumb 5 port switch and plug 4 computers in
possiblylinux127@lemmy.zip 1 week ago
en.wikipedia.org/wiki/IEEE_802.1Q
Vlans are simply a tag on a frame. You can set what if any tags are allowed and you can set the switch to tag untagged traffic. You can can limit Mac addresses with port security.
marauding_gibberish142@lemmy.dbzer0.com 1 week ago
Thank you. Now I just need to learn to do all of this on Linux/BSD lol
neidu3@sh.itjust.works 1 week ago
Yes, but that’s done on the switch. Basically VLAN tags are applied in one of two ways:
Untagged (sometimes called Access) is something you apply on a switch port. For example, if you assign a port to Untagged VLAN 32, anything connected to that port will only be able to connect to port 32.
Tagged (sometimesreferred to as Trunk), on the other hand, is for traffic that is already assigned a VLAN tag. For example Tagged 32 means that it will allow traffic that already has a VLAN tag of 32. It is possible to assign multiple VLANs to a Tagged port. Whatever is connected to that port will need to be able to talk to the associated VLAN(s).
In your particular case, the best practice would be to assign two ports (One for each host, obviously) to Untagged 32 (arbitrarily chosen number, any VLAN ID will do, as long as you’re consistent), and all the other ports as Untagged to a different VLAN ID. That way the switch will effectively contain two segments that cannot talk to each other.
marauding_gibberish142@lemmy.dbzer0.com 1 week ago
Thank you so much for the explanation. I followed everything but:
I couldn’t really understand what you meant here. Did you mean VLAN 32 in the last line?
neidu3@sh.itjust.works 1 week ago
Derp, yes. Corrected.