Pass Public IP through ASA5505

[david_mundt]

I've got a client with an old ASA5505 (Cisco Adaptive Security Appliance Software Version 8.4(4) Device Manager Version 6.4(9) and they have 5 public IPs. I've natted one of the public IPs to the inside address of a SimpleWAN firewall. The SimpleWAN errors out when it sees the natted traffic so if it is possible I'd like to assign one of my public IPs to the SimpleWAN and allow all that traffic to pass through the ASA.

Is this config possible? Thank you in advance for your assistance. 

[Rob Ingram]

Hi,
You get an IP subnet from your ISP and just route through to the SimpleWAN device.
HTH

[david_mundt]

This is precisely what I want to do. My question is I've only got 1 block of 5, 4 of which are being used on my ASA. I want to know if I can assign the simple wan interface the remaining IP and route to it through an interface on the ASA.

[Rob Ingram · Accepted solution]

What I meant was acquire another public IP subnet and route that through the ASA, as you can't route the spare IP address of a network defined on the outside of the ASA to the inside of the ASA.

Alternatively if you say the SimpleWAN device is a firewall, move it's outside interface to the outside of the ASA, by plugging the router, ASA and SimpleWAN device into a layer 2 switch. This does mean the SimpleWAN firewall will not be behind the ASA, but that's all you can do without acquiring another public IP range.