NAT Inside/Outside

[Danilo Dy]

How many inside interface and outside interface a Cisco Router can support?

I was told that it can support only one outside interface and multiple inside interfaces. Is it true? Because I can't find any documentation from Cisco Web Site regarding this. If anyone know where to find it, please direct me to that URL.

I have configured a router with one Ethernet Interface and one Serial Interface. The ISDN for Serial interface will be coming 2 months later. As you should know, I'll be doing floating static route to backup the Serial line with the ISDN Line, in case if it fails. I have a host connected to Ethernet Interface that I need to NAT statically. I use Ethernet Inteface as "NAT Inside" while the Serial Interface as "NAT Outside". If Cisco Router does not support multiple NAT "Outside Interface", I have to change the configuration now before it is too late.

Thanks in advanced.

[olorunloba]

I do not think there are any limitation. Practically though, I've had a working configuration of a 3640 router, with 4 ethernet interfaces, where 2 were nat inside interfaces and 2 were nat outside interfaces.

[jolmo]

I agree with olorunloba. I also have a 3640 with 6 outside interfaces and 15 inside interfaces (Fast ethernet, loopback and serial interfaces) working with no problems.

HTH

[Danilo Dy]

Yup, I test it in a lab. No problem.

I got the message from my vendor. lol, scary.

[n2-goes]

Hello,

You could also use a loopback for the outside interface that will then route either via the serial interface or the ISDN interface.

Nadine.