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Best way to do load balancing between 2 ISPs

David Sanjuan

Hello Everyone,

I need your advice for the best way to do load balancing for the following scenario.

Customer connected to a Business VDSL line with Static IP and some redirected port for service such as FTP.

Add of second ISP, ADSL line with the modem in bridge mode.

We would like to have WAN load balancing between the 2 ISPs.

Currently, they only have an Cisco ASA5505, unfortunately this is not able to do load balancing between 2 WANs. I have read about ways to do it with 2 ASA5505 but this doesn't seems the what I want.

I read about Cisco Meraki, but the MX80 being a yearly subscription is quite expensive.

Based on that, what would be the best way for a small business with not very high budget to do Load balancing between 2 WANs ?

This company has 40 users on site and growing slowly, and we would like to keep the Cisco ASA5505.

Many thanks for your piece of advice.

3 Replies 3

Richard Burts
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When you introduce a second ISP and want to do load balancing it is frequently helpful to think of it in terms of how you balance outgoing traffic and how you balance incoming traffic. In considering incoming traffic it is helpful to know how much of the incoming traffic is in response to requests initiated from inside your network and how much of the traffic is initiated from the Internet to resources in your network. Do you know how much and what type of traffic is initiated from the Internet to resources inside your network?

For a larger company using 2 ISPs we might look at running BGP as a way to achieve load balancing. But it sounds like that might not be a good fit in your situation. So we should look for other options to achieve load balancing for you. Unfortunately the ASA5505 does not provide many options for that. Perhaps you can have a default route going out an interface with the primary ISP and have static routes for certain network going out another interface to the other ISP?





Hello Rick,

Thank you for your answer. Actually, there is not so much incoming traffic and we thought more a solution like

and put the ASA behind but we have 2 differents ISPs. We know that Sonicwall or Zyxel Zywall series have features like this.

We do not really need to have static routes for certain network and others goint to another ISP...




the best way to get this with Cisco is,

get a Cisco Router like -> Cisco RV320 Dual Gigabit WAN VPN Router



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