Frame Tagging

Ted Lemon Ted.Lemon at
Thu Aug 1 21:30:06 UTC 2013

On Aug 1, 2013, at 10:22 PM, George Sexton <georges at> wrote:
> Steven Carr's response was unhelpful, brusque, and basically had an
> attitude. Putting the word please in a sentence doesn't make it polite. It
> wasn't warranted.

I think it's better for people to be nice when they correct each other, but that said, it's bad form to re-post a message you posted the week before without comment.

> I'm just not sure how I can use a switch (assuming I had one that capable)
> in the manner you suggest.

It depends on the switch.   The one I used had a Cisco command line interface that worked, and also a web interface that worked.   I found the command line interface easier.   The syntax on that switch would look something like this:

vlan 10
untagged ethernet 1
tagged ethernet 2

Then you plug the tagged wire into ethernet 2, and the untagged wire into ethernet 1.   I think this is a fairly common syntax on bigger switches, but I don't know what really cheap 802.1Q switches do.

> I don't suppose you have any suggestions for switches I could get cheap,
> used that would have this capability?

It looks like a $59 D-Link managed switch will do it, actually, and it has a web UI that's fairly usable.

> I've done networking for a long time, and never tried to use VLANs before. I
> bought some wireless access points that had it, along with the ability to do
> multiple SSIDs and I thought it would be a neat way to segment my wifi
> network.

Yes, it is pretty neat.

> It would be really nice if dhcpd were doing the right thing here...

Yup.   But it's a substantial amount of coding, and I suspect it bites people _very_ rarely.

Anyway, I hope this helps.   I learned a bit answering your question.   I don't think it would help with your DHCP problem, but you can do 802.1q in your linux machine, if that's what you're using for a server.

More information about the dhcp-users mailing list