I have one router with two ethernet interface.
I am working on allowing two different networks using one physical interface.
I set up a lab environment to test the above.
I commence by sub interfacing the physical (fa 0/0) and created a two logical interface and defined as Vlan 1 and Vlan 10. The addition physical interface is use a wan interface connects to host to simulating a remote site.
For my lan environment I connect a switch to the physical interface of the router .
On the switch I configured one port as vlan 10 and all the other ports are members of vlan 1 by default a trunk port is configured that allows vlan 1 and 10 .
I connect two lap tops to the switch, laptop A connect to vlan1 and laptop B connect to vlan 10 .
Summary of set
Laps connected to switch , switch connect to router thru trunk port to lan side
The second Ethernet ( wan) is connect to host
Results of the lab test
From laptop A I can ping the remote host connected to the wan interface.
From laptop B I cannot ping the host connected to the wan interface.
I observe that laptop A is connect to port on switch defined as vlan1 with by default is native vlan.
If I defined vlan 10 as a native vlan , laptop B is able to ping the remote host.
I am confuse and unsure how to proceed.
Yes as Jon stated you need to make your switchport a trunk port so that it 'tags' frames with the required VLAN tag which the router is expecting (10 in your case). Once you make the switchport a trunk interface things should work.
Attach is the info as per request.
I using the a cisco 3500 xl switch and the command 'show interface trunk' is not returning any info i think this command is missing on this switch.
Any the other info is provide.
Is fa0/48 the uplink to the router ? ie.
switchport multi vlan 1-250
switchport mode multi
if so this is not a trunk. You need to change the config -
switchport mode trunk