I have a connection to a network service provider with two VLANs on it.
One VLAN has the internet. The service provider has defined a default router and assigned me a subnet of IPs attached to that router for me to use.
The other VLAN is a connection to two remote sites.
(It is set up this way for historical reasons.)
What I really want to do is use the IPs assigned to me on the second VLAN.
So. Is there any reason why I can't:
- untag a port on the internet VLAN
- untag a port on the remote-site VLAN
- turn spanning tree off on those two ports
- connect them together with a crossover cable
...besides the fact that it just looks wrong?
Second part of the question.
Assuming I have a Dell PowerConnect 6224, is there a way to do this "correctly" within the switch without the wrong-looking cable?
...and the answers, are:
1) Because it IS wrong. If you create an ethernet loop across VLANs as described, even if you have spanning tree turned off on the ports in question (or even the entire switch) -- if you have spanning tree ANYWHERE ELSE in your network, those packets will loop and flood all ports on the switch.
2) Call the service provider and ask that a /30 be set up between you and them; then have them route the /26 to you via your end of the /30, which you've assigned to one interface on your 6224. Then put the /26 on VLAN2 through another interface. Enable routing, and you are done.
Yes, the thing that does what you want is called a "router".