need help on vlan

Unanswered Question
Apr 26th, 2007

If the e0.1 and e0.2 interface of a router has an ip add of and respectively both having subnet masks of, and this e0 port is connected to a switch, what should vlan1(management vlan) ip add be? What subnet should it belong to?

Thanks in advance to anyone who can help.

I have this problem too.
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Jon Marshall Thu, 04/26/2007 - 10:55

Hi Mark

Is the switchport that is connected to e0 configured as a trunk ?

It is entirely up to you as to which subnet you make the management subnet. What are the 2 subnets 192.168.1.x & 192.168.2.x being used for at the moment ?

Good practice is to use a separate subnet for management of the switches so if you have users in the 192.168.1.x & 2.x subnets use another subnet, create a subinterface on your e0 interface and use that as your management vlan.

Hope this makes sense. Let me know if you have any other questions.


marcusbrutus Fri, 04/27/2007 - 01:42

Thanks Jon for the reply and the info. I am currently working on Boson netsim and am trying to create a couple of vlans on a switch connected to a router. The configuration i have inputted so far are the ff:

On the router:

1. no ip add on the e0 int, no shutdown

2. ip add of on e0.1, no shut, encap dot1q 10

3. ip add of on e0.2, no shut, encap dot1q 20

4. ip add of on e0.3, no shut, encap dot1q 30

On the switch:

1. On f0/1, switchport mode trunk, switchport trunk encap dot1q

2. vlans 10, 20, 30 added to the vlan database - all named A, B, C respectively

3. port f0/2 added to vlan 20

4. port f0/3 added to vlan 30

5. vlan 1 given ip add of

with default-gateway of

The problem is that after i have configured all this and then check router by ip route and ip int brief, there is no route pointing to any network and the subinterfaces are all down on layer two respectively. I have been troubleshooting this problem for sometime and i have to admit that i might probably lose my mind really soon if i can't get this simple setup to work.

I would appreciate any help you can give me regarding this. And thank you in advance.

Jon Marshall Fri, 04/27/2007 - 02:04

Hi Mark

1) Are you seeing nothing if you do a "sh ip route" or are you seeing directly connected networks in the routing table.

If you are seeing nothing type "ip routing" in config mode.

2) Can you check the speed/duplex setting between your e0 interface on your router and f0/1 on your switch.




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