Port 3 of ASA 5510 firewall use to let outside traffic through to VPN router.

Dear Experts,

I need to let an ASA 5510 port let outside traffic pass though. I made its security 0 and gave it neither an external or internal IP address. That is the question. What else should I do to that port to it lets VPN traffic pass from another office to a cisco VPN router.

This is what it looks like:

interface Ethernet0/3
 nameif To_VPN_router
 security-level 0
 no ip address

Will this let outside traffic pass to the Cisco VPN Router?
marceloNYCMiddle-Tier AdministratorAsked:
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Marius GunnerudConnect With a Mentor Senior Systems EngineerCommented:
In this case, yes a switch would be the easiest to get this working.
Marius GunnerudSenior Systems EngineerCommented:
Well the interface would need an IP. It is required that it has connectivity to the remote site, or remote users if it is remote access VPN.  Once you have established connectivity to the outside host/hosts and assuming that the VPN is configured correctly, things will start to work.
marceloNYCMiddle-Tier AdministratorAuthor Commented:
Yeah the VPN router is working right now using another ISP. We had change ISP and have no other interface available other than the one from the ASA. So you are saying I need to give this interface an external IP address and what else?

Should I use a switch instead?

I need to make the VPN router change its way to the internet over the ASA.
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Marius GunnerudSenior Systems EngineerCommented:
If you could elaborate a bit more on what you are trying to do please.

Right now, yes you need an IP on the interface, also you would need to configure routing out that interface.  depending on your requirements you would either set up static routes pointing out that interface or you would set up a default route.  I would need to know more about your situation.  Will this be your primary ISP?  Will the ASA be the default gateway for your hosts? Will the existing VPN router still be used for something? will the existing ISP that the VPN router is using still be used?  Is the ASA only going to be used for VPN?
marceloNYCMiddle-Tier AdministratorAuthor Commented:
Okay, I need to make the VPN router access the internet with the new ISP. I have a ASA firewall connected to the AT&T Router. There is only one ISP now the other two and going to be discontinue.

I don't want the ASA to be the default gateway of the VPN router.

The ASA is not going to be use for site to site VPN .
The existent VPN router needs to change its public IP address and access to the web. Using the access the ASA has right now.  

So is it easier to use that 3rd port in the ASA firewall or should I put a switch in between the  ISP (AT&T router) with the ASA and VPN router.

remote vpn offices <--------------------------------------> ISP  AT&T router <---> ASA 5510

How do I get the VPN router to work with that order above. It is going to have its dedicated ISP line discontinue.
Marius GunnerudSenior Systems EngineerCommented:
I would give the AT&T router the new public IP if it doesnt have it allready, then assign an IP to the inside interface of the AT&T router (or is it configured as the DHCP server?), then ad an IP to the ASA outside interface so that it has connectivity with the router, then configure access rules, NAT (if needed), and routing so that the ASA can reach the remote clients (again if needed) and the internet.
marceloNYCMiddle-Tier AdministratorAuthor Commented:
No, The AT&T router is not managed by me. I have our Cisco VPN router and that ASA behind the AT&T router to the internet. I am thinking of using 3 switch ports in a switch with its own VLAN. I need to figure that one out. I am not liking using the third port for the ASA Anymore.
marceloNYCMiddle-Tier AdministratorAuthor Commented:
Thank you for your time on this. It is good to have an experts opinion on the side :)
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