Handling of target IP addresses in rule for outbound endpoint

Question

I have some rules for forwarding domains using outbound endpoints in the Route 53 resolver.  I specify multiple target IP addresses in each one.  
  
I can find no documentation on the handling of the list of IP addresses.  Does the resolver start at the top of the list and fail-over only as needed, round-robin over all the addresses, or....?   This behavior does have some implications for how I optimize the list of targets.  
  
Thanks.

AWS-User-6179575 · Answer

Hi,  
  
I updated the doc. In the section "Values That You Specify When You Create or Edit Outbound Endpoints," see "Order of IP addresses":  
  
https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/resolver-forwarding-outbound-queries.html#resolver-forwarding-outbound-queries-endpoint-values  
  
Thanks for raising the question.  
  
Scott

AWS-User-6179575 · Answer

Hi,  
  
I checked with the devs, and they said, "The order of the IP addresses has no effect on which target Resolver chooses." I'll add that to the doc.  
  
Scott

jradel · Answer

Thanks.

Handling of target IP addresses in rule for outbound endpoint

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