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Assigning a second external IP address to ASA 5505

robbhanMid
Level 1
Level 1

Hi,

I have a working asa 5505 installation that I would like to configure for one more external IP address. My problem is when I try to create a second outside interface, called outside2 for example, i get an error message say that the subnet is overlapping with the previously configured outside interface. This probably makes sense but how do I assign a second, or even a third, external IP address to my asa.

Our ISP gave us five public addresses so I figured I'd use at least a few of them.

Thanx

2 Replies 2

robbhanMid
Level 1
Level 1

I solved it my self.

The best way to assign multiple IP addresses to one interface is to use static nat.

For example:

static (inside,outside) x.x.110.250 192.168.1.250 netmask 255.255.255.255

static (inside,outside) x.x.110.251 192.168.1.250 netmask 255.255.255.255

Hi Robert,

Just to correct perhaps minor typo, your current static entries that uses two different public IP addresses mapped to a single inside host of 192.1678.1.250 can only be possible through Policy NAT as it is not possible through static NAT to map two or more global addresses to a single inside host.

I think your static nat entry was meant to map a second public IP to a different host inside your LAN which is general practice when ISP hands out a block of public IP addresses for their clients to use.

Your static perhaps meant to be towards two inside hosts 192.168.1.250 & 251 or perhaps some other host other then 250.

static (inside,outside) x.x.110.250 192.168.1.250 netmask 255.255.255.255

static (inside,outside) x.x.110.251 192.168.1.251 netmask 255.255.255.255

Regards

Jorge Rodriguez
Review Cisco Networking for a $25 gift card