Outbound Policies - Domain name

So I’ll try to explain the issue with Fastest Response in relation the secure websites, then I will attempt to explain why it works for some people, but it’s not a good idea to set things this way as it will cause you issues randomly and you won’t be able to troubleshoot.

  1. You type into a browser www.google.com
  2. Your computer looks up www.google.com via DNS on one of your WAN links
  3. Your computer requests http://www.google.com on both WAN links
  4. The fastest response comes in from WAN1 saying re-direct to https://www.google.com
  5. Your computer requests https://www.google.com on both WAN links
  6. The fastest response comes back from WAN2.
  7. Your computer requests the image on the google homepage on both links
  8. WAN1 has the fastest response, but it’s a SSL handshake start, rather than the image
  9. WAN2 responds with the actual image, but it’s discarded because WAN1 responded faster
  10. You see a missing image on google’s homepage.

This example isn’t the common one. The common one is banking websites because they require secure images so they know malware isn’t being loaded into your browser.

I have tried to run Fastest Response, Weighted Balance, Persistent Destination and had problems with each of them, therefore I rely on the ultra compatible Persistent Source with custom Weighting. Now this is because my WAN links have almost identical latency characteristics. So I have responses come back almost simultaneously on both links. If your WAN’s are always out of balance with each other… IE one has 100ms while the other has 25ms… you won’t have any issues with fastest response. So this is something that really depends on the situation. Hopefully this explanation helps.

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I have tested hundreds of websites, not a single issue as you describe, including dozens of banking websites. Maybe I am just lucky? But my understanding is pretty much all websites have adopted to the fact that packets can be coming from different places for the same session. A good example is people using WiFi and cellular on their phones, going in and out of range of one or the other, and the session doesnt error out.