My DNS has resolved, but my site won't serve

Matt Riches 1

All of this is on Azure

have 2 vps behind a loadbalancer.

1 VPS is currently off to eliminate loadbalancer issues

loadbalancer has http and https (ports 80 and 443), both ports are mapped front end to back end.

on one vps I have added a letsencrypt cert (DNS verified) to a site.

pinging the domain name points to the LB so the domain has propogated

navigating to https://testdomain.com throws up an ERR_CONNECTION_TIMED_OUT

navigating to https://www.testdomain.com throws up an ERR_CONNECTION_TIMED_OUT

navigating to http://testdomain.com throws up an ERR_CONNECTION_TIMED_OUT, but inspecting the url it has somehow reverted to https://testdomain.com

before I deployed the site I was using a test domain. This test domain still serves the files so I know the site is fine.

I want to say that this is just propogation, but being as ping finds the site via its name, I don't believe that this is the case, unless ping uses a different dns to everything else.

So have I missed anything obvious to try here, or is this really just a propogation issue, and ping sitename is somehow working faster than the rest of the dns?

Sam Wu-MSFT 7,036 Reputation points Microsoft Vendor

2021-07-01T02:10:30.827+00:00

@Matt Richer According to your description, it is difficult for me to reproduce your problem. Can you tell me how to configure your loadbalancer?
Matt Riches 1 Reputation point

2021-07-03T13:25:35.417+00:00

Apologies, It looks like the issue is with the load balancer. If I change my DNS to point direct to one of my servers, then it all works, http and https.
If I go back to the load balancer then only http works.

Load balancer has 2 Front end rules, http and https (ports 80 and 443)
Each Rule maps direct front to back end (so 80 -> 80 and 443 -> 443)

The Back End pool has both my servers in it.

Both Web servers associate with an NSG that allows 80 and 443 traffic to flow both ways.

Its certainly a configuration / understanding issue on my side, but I can't figure it out, and I am just going round in circles!
Sam Wu-MSFT 7,036 Reputation points Microsoft Vendor

2021-07-05T08:47:24.72+00:00

@Matt Riches It seems difficult to troubleshoot your problem, I suggest you open a support ticket for this, one of our engineers will help analyse the root cause.
Matt Riches 1 Reputation point

2021-07-07T15:04:05.123+00:00

II have been doing some reading and research. I think I need to configure my Loadbalancer to reverse proxy 443 as http works fine, so its just the https thats the issue now.

I need to do some reading, but I hope that this is possible on the standard Load balancer ?
Sam Wu-MSFT 7,036 Reputation points Microsoft Vendor

2021-07-08T07:39:46.343+00:00

@Matt Riches Regarding reverse proxy, this link should help you: reverse-proxy-with-url-rewrite-v2-and-application-request-routing.
Matt Riches 1 Reputation point

2021-07-09T17:53:15.18+00:00

Thanks. II am not sure that helps me right now.
I have removed one of the servers and made it public facing. So now I have

Load Balancer -> http and https allowed through -> Single IIS instance. Http traffic passes through, https doesn't. I can see in IIS logs that https calls are not even being logged. In fact I get This site cannot be reached ERR_CONNECTION_TIMEOUT.

My other vps has the same site and iis config, but I am hitting it direct to its IP, cutting out the loadbalancer, and http and https work.

My loadbalancer has 2 public rules, http and https mapped directly to one backend pool that contains my vps. The NSG is allowing http and https traffic through.

So I am at the limit of my knowledge here, and sadly do not have a paid support plan so I can't raise a ticket. It has to be something silly I have done, I just can't see it.