0

I'm having the following dilemma, I have a website on IIS with two internal IPs, each one of those IPs are NATed to different external IPs (each IP is from a different ISP). I also configured a RoundRobin DNS Service (two A hosts with the same name but with a different IP). Basically what this does is that the traffic is balanced between the two ISPs, and that's what we want. The thing is that apparently this configuration (DNS Roundrobin) is meant for when you have a cluster of server so each server has its own ISP on its own NIC, so the traffic from the webserver to the client is made over that ISP.

Right now we are being told that no matter where our inbound traffic comes from, the outbound traffic is always through our main WAN, which is also OK, because we have tested that when the primary WAN link is down, the website keeps working on the secondary link.

OK, the question is, do you think there may be problem with this configuration? Is the DNS Rounrobin also useful on this configuration?.

Thanks a lot for your feedback.

Armando Andrade
  • 11
  • 2

1 Answers1

0

normally when you host a web service the responses are much bigger compared to the inbound traffic (normally you receive an HTTP GET/ and deliver the whole content back) - so it would make much more sense to balance the outbound traffic over your ISPs to get value out of your additional bandwidth.

does it make sense - yes - you can loose one ISP and your site is still available (assuming you do Healthchecks on your DNS server to determine if the sites are available before you send the IP address back - if you always deliver both IPs even when one ISP is down it won't help you at all)

it would be better to add an additional server - OR do policy based routing on your single server - so sending the response out of the interface where it was received.

hope that helps!

roegi
  • 183
  • 1
  • 16