Monday, April 26, 2021

Help w/ port-tagging / vLAN issue on Cisco 4321 router

I have a Cisco 4321 router that is currently connected to a Verizon internet connection. The Verizon internet connection requires port tagging on vLAN 40 in order to see their network. As such, I have configured the port like this and can successfully ping Verizon's default gateway (xx.xx.xx.13) and other IPs across the internet.

interface GigabitEthernet0/0/0

description Verizon

ip address xx.xx.xx.14 255.255.255.252

no ip redirects

no ip unreachables

no ip proxy-arp

negotiation auto

port-tagging

encapsulation dot1q 40

set cos 0

My next step is to test connectivity from a workstation. I have set gi0/0/1 to have an IP of 192.168.0.1 and setup a workstation to connect to it with an assigned IP of 192.168.0.2. When I have the port set like this, it can ping gi0/0/1 (192.168.0.1), gi/0/0/2 (xx.xx.xx.14), but not the Verizon default gateway (xx.xx.xx.13).

interface GigabitEthernet0/0/1

description LAN Facing Internet Subnet

ip address 192.168.0.1 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

negotiation auto

I am of the belief that port-tagging to identify the traffic as part of vLAN 40 is potentially the culprit. As such, I have attempted to configure gi0/0/1 like this:

(1st attempt)

interface GigabitEthernet0/0/1

description LAN Facing Internet Subnet

no ip address

no ip redirects

no ip unreachables

no ip proxy-arp

negotiation auto

!

interface GigabitEthernet0/0/1.40

encapsulation dot1Q 40

ip address 192.168.0.1 255.255.255.0

(2nd attempt)

interface GigabitEthernet0/0/1

description LAN Facing Internet Subnet

ip address 192.168.0.1 255.255.255.0

no ip redirects

no ip unreachables

no ip proxy-arp

negotiation auto

port-tagging

encapsulation dot1q 40

set cos 0

...however, the workstation cannot ping gi0/0/1 nor can the workstation be pinged from the 4321 router.

What am I missing to get the workstation to use the internet through the router in this scenario?



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