Need for Edge Router in addition to ASA?

[anord]

Hello -

I am looking for some guidance and clarification.  We just got new service with an ISP for a new building that we will be moving to shortly.  I was at the site and tested the connection from my laptop and verified we have service.  Now I am in the process of planning what equipment I need and how it will all interconnect.

The connection hand off from the ISP is Ethernet.  The connection from the ISP to us is a /30 and they also gave us a /27 block of IP addresses.  My main question is do I need a dedicated router where the /30 network ends and the /27 network begins or can I use the ASA?  I guess I am not sure how the ASA would be configured in this scenario other than the outside interface would be in the /30 subnnet.... how can I use the /27 block in this scenario?  Would the /27 public block be in it's own DMZ?

I am trying to avoid having to buy a router for the simple task of going between the two networks when we are already going to use the ASA for routing.

Thank you.

[jmunoz19]

You do not need a router in this scenerio since the handoff is ethernet.  Use the /30 on the outside interface.  The /27 can be used with static statements.  Even though that network is not on the outside interface, the ASA will still answer and respond to those addresses.  I've setup several customers like this.

If you feel more comfortable with one network, you could ask the ISP just route the /27 and not the /30.  Either way will work for you though.  Bottom line is that if it's just an ethernet handoff you don't need a router.

[anord]

Thank you for the reply.

Would you be able to provide an example of what the ASA config would look like in this scenario?