Issue with 3750 as Gateway

Unanswered Question
May 19th, 2008

On a single LAN with two independent IP networks, will a 3750 switch used as the gateway keep traffic between networks off of the router? Can a single switch (or stack) be configured as gateway for each independent IP network?

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
connectone Mon, 05/19/2008 - 18:36

the 3750 lets you set ports up as router ports by using the no switchport command. I would take two ports, set them up as router ports and have one setup for independant IP network A and set the other to independant IP network B. You only require one Vlan so all other ports would belong to the single Vlan you had mentioned.

Make sure IP routing is turned on and set the routes for reachable subnets over the two IP networks so your single vlan could interact with systems behind those networks.

So the 3750 can be a gateway as long as IP routing is turned on and you add the appropriate routes (static or with a routing protocol).

Hope this helps. If you need help with commands let me know.

Richard Burts Mon, 05/19/2008 - 19:04


I am not clear what you mean when you say:

"On a single LAN with two independent IP networks"

if it is a single LAN then to me that suggests that there is a single VLAN. And I do not see how you are going to associate 2 routed ports with a single VLAN.

And from a topological perspective I am not sure that if they are in the same LAN/VLAN that two IP networks can really be independent. They would be in the same broadcast domain and therefore not fully independent.

Perhaps you can clarify what your topology is and what you are attempting to accomplish. Then perhaps we can provide better answers.




This Discussion