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One Gateway with 2 vlan's

inf2300
inf2300 asked
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Last Modified: 2012-08-13
Hi,

I have a 3com 4500 switch and I've setup 2 vlan's (1 & 2) on it.  I'd like both vlan's to use the same gateway to access the Internet so I've plugged my router in a trunk port on that switch.  I don't seem to be able to ping my router from a vlan2 access port so there's something I probably don't quite understand about vlan's.
My trunk port permits traffic on all vlan's so shouldn't it let the ping from vlan2 through?  I've also plugged my router in a hybrid type port on the switch with the same result.

I need a quick answer on this,

thanks!
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Commented:
O.K.

You have VLAN1 = 10.1.1.0/24
              VLAN2 = 10.1.2.0/24

I will assume that your router has an IP address in VLAN1.  Does it have an IP address on VLAN2?  If not how is it supposed to get back to VLAN2?

Commented:
You need a separate interface for VLAN 2. Your VLAN 1 works above because it's the native VLAN of the trunk and so is untagged.

Let's hope you have a Cisco router that supports what you want to do.
You need to create a subinterface for the ethernet port connected to the trunk, configure trunk support and then the IP address/mask of the VLAN 2 gateway.

For instance, if connected using FastEthernet 0:

interface  FastEthernet 0/0.2
  encapsulation  dot1q  2
  ip address <address>  <mask>







Author

Commented:
Giltjr,

My plan was to use the same subnet (10.1.1.0/24) for vlan1 & 2 because my router (watchguard x50) can only take on IP.  By having my router act as my dhcp server, I would make sure no IP's would conflict.  I need to have 2 separate networks (internal & customers) using the same internet connection.   I don't understand why I can't ping my router from a station in vlan2 (10.1.1.5) if i'm using the same IP range on my router.(10.1.1.1)

Is what i'm trying to do impossible with my current hardware?
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