ASA 5508-X and Asus RT-AC68U

[kellylewis]

Hi

I have just joined this forum as I feel I can learn a lot from it, and hoping you all can help me on my first post (hopefully posted in the correct place?!)

I am fairly new to Cisco (I have had experience in old jobs, however had never had to set one up from scratch). I have recently purchased and ASA 5508-X for my company, mainly for the VPN compatibility which I believe will benefit us a lot, however I am unsure how to connect this up to the current setup.

At the moment I have an Asus RT-AC68U that connects to our main line in from outside and this issues DHCP Addresses to everything connected. However, now I would like to introduce the ASA I am unsure how this can be done. Obviously if I connect the firewall to the Main line in and then plug the Asus in to the firewall, no addresses will be issued so will stop internet connectivity etc (I think)!? but then if I connect Main Link - Asus - Asa, then this will also stop addresses being issued!?

I think I might be confusing myself, but any help would be much appreciated.

Many Thanks

[Ajay Saini]

Hello,

Is the ASUS router assigning the public ip addresses to your devices?

Ideally, you can install ASA as a layer 3 hope and configure it as DHCP relay so that even devices behind the ASA can get ip addresses from ASUS router. But how will ASA get an ip address on outside to be able to form a vpn tunnel.

If the ASUS router is only providing private ip address, you can use ASA for that purpose.

If I misunderstood the issue, please rephrase with a diagram if possible and more details.

HTH
AJ

[kellylewis]

Hi Ajay, 

Thank you for your reply, the Asus is assigning private IP Addresses and is also being used as an AP for wireless devices.

I have attached a basic diagram which I hope helps a little, this shows the current setup without ASA installed.

Hope this helps.

[Ajay Saini]

How are you planning to connect the ASA anyways, how will it obtain public ip address - is it static or dhcp based?

what will be the gateway and how will it be reachable? 

What is the issue if you connect the ASUS and ASA on the same external switch and through DHCP you provide the ip address and the gateway of the ASA interface.

HTH
AJ