topic Re: How to route traffic via two different ISP from Cisco ASA 55 in Network Security

How to route traffic via two different ISP from Cisco ASA 5510 simultaniosly

Lasandro Lopez — Tue, 12 Mar 2019 02:39:51 GMT

Hi.
I want to configure two different ISP to my Cisco ASA 5510 (on two different interfaces).
now, i want some IP, to route defaul traffic to internet via ISP01.
Some other internal IP to route default traffic via ISP02.

So, is this possible?
also, i want to track connectivity on ISP01, if it fails, all the traffic to be routed via ISP02.
Regards!

How to route traffic via two different ISP from Cisco ASA 5510 s

Peter Koltl — Tue, 17 Sep 2013 18:22:49 GMT

Load sharing (part of the traffic on ISP02 link) - no.

Backup ISP link - yes.

You can use static route with object tracking to detect ISP01 failure and re-route outgoing traffic to ISP02

How to route traffic via two different ISP from Cisco ASA 5510 s

Lasandro Lopez — Wed, 18 Sep 2013 07:39:56 GMT

So, there is no way to use two ISP on the same time?

Re: How to route traffic via two different ISP from Cisco ASA 55

vishaw jasrotia — Fri, 20 Sep 2013 09:05:48 GMT

Hey Las ,

you can try this by disributing the load :

route ISP1 128.0.0.0 128.0.0.0

route ISP2 0.0.0.0 128.0.0.0

Hope this helps you.

Thanks & Regards

Vishaw

Re: How to route traffic via two different ISP from Cisco ASA 55

Lasandro Lopez — Fri, 20 Sep 2013 10:44:07 GMT

Hi vishaw!
Your proposal is not clear.

What is that 128.0.0.0?
What you are referring with "ISP1" and "ISP2"?
Regards!

Re: How to route traffic via two different ISP from Cisco ASA 55

vishaw jasrotia — Mon, 23 Sep 2013 04:22:31 GMT

Hey Lopez,

With this your half internet traffic will go through ISP 1 and half will go through ISP 2.

till 126 subnet the traffic will take ISP 1 as gateway

And For the remaining , traffic will take ISP 2 as gateway.

Thanks & Regards

Vishaw

How to route traffic via two different ISP from Cisco ASA 5510 s

Jouni Forss — Mon, 23 Sep 2013 07:15:38 GMT

Hi,

To effectively use 2 ISP links on an ASA you would need to be running 8.4(x) software or higher.

This would enable you to use NAT to select what ISP link each LAN network uses. Though with this kind of NAT setup the NAT configuration becomes more complicated to manage. I am also not sure if this setup would be able to reach to ISP links going down as with the NAT configuration we are specifically overriding the routing table and using the NAT to decide the interface through which the traffic goes.

So the setups you can do are atleast

2 ISP setup with a single active ISP for outbound connections at a given time (ISP Failover)
2 ISP setup with NAT configurations to utilize both ISP links at the same time for outbound connections
2 ISP setup with the mentioned way of routing part of the IPv4 address space through each ISP link. Though I wouldnt personally use this.

- Jouni

How to route traffic via two different ISP from Cisco ASA 5510 s

Lasandro Lopez — Tue, 24 Sep 2013 10:29:51 GMT

@Peter
Suppose i want to use for failover ISP02. How i've to configure the NAT rules?

@Jouni

Which method you are suggesting as last and better option?

For all of you.

What about VPN??? does it work simultaniosly with both Real IP of ISP?