How to setup failover to second modem for high availability websites


Active Member
Hi everyone,

This is regarding networks with self hosted websites outside of KH.

Most of my clients just have 1 site which I'd normally host through KH, or have a few non-critical sites that they're fine with being down in the event of an ISP issue. However, one client of mine has websites hosted on site that absolutely need to be up.

Client already has 2 internet modems from 2 different ISPs. I set up a sonicwall which does a great job with failover for their user's internet access, but I'm unsure of how I can set it up so if one modem goes down, websites are still accessible using the second IP/modem. I thought that was the point of a second nameserver, but I was just proved wrong when the primary modem went down. Someone mentioned DNSSEC (?) but no clue on that.

What are your thoughts?
Hi Josh,

Just from what quick reading I did it seems like without going to the huge expense of a high availability network and load balancers that doing a kind of Round Robin DNS would work.

Put multiple A records (one for each ISP) into the DNS server for the site. Both ISPs will see traffic in a normal condition, whichever resolves fastest I'd think, but in the event of a failure the user would see a delay until their system switches over to the other IP.

The next question becomes where is their DNS server? If it's also internal then it should be moved externally because if it becomes unavailable the above becomes a moot point.

Hope that helps and be sure to let us know how it works out!
I'll give that a try. Thanks @Dan
The DNS server is hosted off site. That would explain why the two nameservers didn't do anything for the issue, still pointing users to the bad server.