VLAN Routing Tagged and Untagged (Newbie)

[GrifTTU]

Greetings All

I am fairly new to the world of VLAN, and I'm curious if a scenario would work.

I have ProCurve 6600 series switches.

I have multiple VLANs in play, but for this particular scenario, I'm dealing with 10 and 20.

On one end, I have a server that is:

                not tagged with a VLAN

                plugged into port 1 that is untagged 10

                has an IP address of 192.168.1.1

On the other end I have a server that is:

                 tagged 20,

                 plugeed into port 2 that is tagged 20

                 has an IP address of 192.168.2.1

Both servers have an explict route that allows them to talk with one another (assuming they were on the same VLAN)

If I were to simply tag port 1 with VLAN 20, would the routing between the two work?

My gut says no, because the traffic from the untagged server would be tagged with a VLAN of 10 once the traffic hit the switch.

My coworker says that since the port is both untagged 10 and tagged 20 that the traffic would be tagged appropriately based on the network the traffic is destined for.

[Fredrik Lönnman · Accepted solution]

You coworker are wrong, or maybe it was bad wording ;). If the port is untagged vlan 10 and tagged vlan 20 that means that incoming untagged packets will be accepted and put in VLAN 10 internally in the switch. Incoming tagged packets must have dot1q tag 20 or they will be discarded. 

Pretty much the same on outgoing packets; outgoing packets from VLAN10 will egress the port without a tag, and packets in VLAN20 will keep its tag 20.

[GrifTTU]

That what I was thinking. So, inorder to get the routing to work, we would use a command like the following to enable routing between the two VLANs on the switch?

ip routing
vlan 10
ip address 192.168.1.0/24
vlan 20
ip address 192.168.2.0/24

[Fredrik Lönnman]

Yep, and configure the IPs of the 6600 as default gateway of the servers/clients. 

[GrifTTU]

Perfect. Thank you much for the help.