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Forum Discussion

sricharan61's avatar
sricharan61
Icon for Cirrus rankCirrus
Oct 14, 2019

APM Oauth client gives a HTTP 503 Service unavailable, DNS lookup failed error

I am trying to setup Azure AD as the Oauth server for the APM policy i have on the F5. When using the authorization grant flow and testing a VIP using the policy. I see that the user is redirected to...
application delivery
BIG-IP
BIG-IP Access Policy Manager (APM)
luevelvet's avatar
luevelvet
Icon for Altocumulus rankAltocumulus
Oct 16, 2020

Did you ever figure this out?

 

We're running into a similar issue where we see "HTTP error 503, DNS lookup failed" when attempting to hit an introspection service to validate an oauth token.

 

I'd like to read more about what this DNS Resolver actually does because from what we've seen, it's makes no difference whatsoever.

 

Cheers!

boneyard's avatar
boneyard
Icon for MVP rankMVP
Oct 19, 2020

sorry no solution for initial problem, but do you see a DNS request going out of the big-ip? either via TMM or mgmt interface?

 

can't find a good K article on the DNS resolver configuration. i see it as a way to use different DNS servers then the one you configure for the box. also that traffic will always go via the TMM interfaces.