CNAME record for a verified custom domain

Question

CNAME record for a verified custom domain

leelGS 20

I set up my custom domain successfully (verified & deployed) using the TXT and A records as supplied by the Azure portal.

However, my domain reg (WIX) requires CNAME input to be able to complete the link.

I have tried to reconfigure the custom domain in Azure and still get the TXT & A record values for verification.

How can I get the CNAME records from Azure to input in my domain registry?

Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-02T13:47:17.09+00:00

Hi thanks for the question
To help us understand better - are you referring to the final step of linking your custom name, you want to CNAME your domain record to Azure App Service so the custom name then points at the web app?
leelGS 20 Reputation points

2023-08-02T16:31:51.8233333+00:00
thanks for your question. I have linked the custom domain name on the Azure portal (I hope rightly)

I updated the A and TXT records on the domain registry platform (the records are provided by Azure after you enter the domain name while setting it up)

clicked verify on the Azure portal after the entry and everything went ok. I can see the custom domain name on the Azure portal

However, I cannot get to the domain when I type it on a browser

wix says I must update the CNAME record.

So I am seeking how to obtain the right CNAME record to update in Wix - to complete the link

Hope this puts some context

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Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-02T13:47:17.09+00:00

Hi thanks for the question
To help us understand better - are you referring to the final step of linking your custom name, you want to CNAME your domain record to Azure App Service so the custom name then points at the web app?
leelGS 20 Reputation points

2023-08-02T16:31:51.8233333+00:00

thanks for your question. I have linked the custom domain name on the Azure portal (I hope rightly)

I updated the A and TXT records on the domain registry platform (the records are provided by Azure after you enter the domain name while setting it up)

clicked verify on the Azure portal after the entry and everything went ok. I can see the custom domain name on the Azure portal

However, I cannot get to the domain when I type it on a browser

wix says I must update the CNAME record.

So I am seeking how to obtain the right CNAME record to update in Wix - to complete the link

Hope this puts some context

Answer 1

Ben Gimblett 4,560 Microsoft Employee

Hi - OK

So to illustrate. I have purchased a domain name "contoso.com" and I have created a web app called "contoso"

The web app by default is addressable on the Microsoft owned default domain name and listens on "contoso.azurewebsites.net" therefore from a browser I could access "https://contoso.websites.net"

By following the steps (as you have done) to add a custom name (in my example here "contoso.com") I'm achieving two things
(1) I'm telling my web app to listen for incoming requests that have a host header matching "contoso.com" (as well as the default name

(2) I'm confirming ownership of that domain (that is the bit with the TXT record)

The final step is then to go to my public name provider (WIX in your case) and CNAME "contoso.com" to "contoso.azurewebsites.net"

Hopefully that makes sense - obviously your host name and web app name will be different.

WIX provide a support page with instructions on how to add a CNAME https://support.wix.com/en/article/adding-or-updating-cname-records-in-your-wix-account

So if I was hosting with WIX my "hostname" would be "contso.com" and my "value" would be "contoso.azurewebsites.net" (I have never used WIX so hopefully I got that the right way around!). The "TTL" is "time to live" and you typically choose the default value (it denotes how long a DNS lookup should be cached before being refreshed)

Once you've changed settings against a public DNS entry it does take time to propagate - there should be a note about that when you save the changes. You can use "dig" https://www.digwebinterface.com/ or a command line name lookup tool to confirm your hostname is resolving properly (and of course you can simply test in browser)

Important note: Even after all these steps, if I want to access my website over SSL "https://contoso.com" then I'll need to ensure I also purchase a SSL cert which matches my host name ("contoso.com" in my example)
There's a number of options for web apps explained here https://learn.microsoft.com/en-us/azure/app-service/configure-ssl-certificate?tabs=apex

Hope this helps

Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-02T17:29:06.16+00:00

please mark the answer accepted if it answers your question as this is helpful to others
leelGS 20 Reputation points

2023-08-03T12:33:01.1133333+00:00

Thanks for your carefully spelled-out steps. very useful. What I did in Wix was to add the following (see attached):

They already had .leelaurelsgs.com kind of hard-coded in their system

I added www in the blank space before the .leelaurelsgs.com and then added the value record.

Hope it works

wix4Screenshot 2023-08-03 133007.jpg
Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-03T13:30:15.19+00:00
Yes that looks OK

A "www" prefix is should be CNAME to your root (or Apex) domain "leelaurelsgs.com"

from the screen shot provided it looks like "www.leelaurelsgs.com" points to the default azure website name (as you've configured it)

From Dig UI

www.leelaurelsgs.com. 3600 IN CNAME leelaurelsgs.azurewebsites.net.
Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-03T13:38:36.4133333+00:00

Edit

Sorry my original post I missed an important point that I'd forgotten about

**

When you're using custom names and public DNS you have in effect two things

A naked/root/apex domain - for example "contoso.com"
Optionally a subdomain prefix - for example "www.contoso.com"

We generally advise people to CNAME (rather than use an A record) because the public IP of App service can change under certain circumstances https://learn.microsoft.com/en-us/azure/app-service/overview-inbound-outbound-ips#when-inbound-ip-changes

However there's also an historic issue to consider (the bit i forgot in the prior edit)
Technically you cant CNAME an apex domain (so i cant add a CNAME for "contoso.com")
One of the better debates on this is here https://serverfault.com/questions/613829/why-cant-a-cname-record-be-used-at-the-apex-aka-root-of-a-domain (but it's not the most straight forward read)

What that means is that you have two choices

You can assume most people will go to your site using the www prefix "www.contoso.com" and have any traffic coming in with "contoso.com" redirect to "www.contoso.com"

You can serve both by using an A record for "contoso.com" and a CNAME for "www" towards the default azure web site address (which is what I think you've done, because the nslookup / dig shows that)

The key point here is that unless the redirect is achieved somewhere else (not on the web app itself) you need a binding for both... in otherwords App service needs to listen for both "www.contoso.com" and "contoso.com" - furthermore your SSL cert needs to match both too

If you request a host name and app service cant match it you get a 404

When I look at your website the apex/root "leelaurelsgs.com" works fine but the SSL cert subject is "leelaurelsgs.com"
If I try "www.leelaurelsgs.com" I get a 404 from web apps and a SSL error. The former is probably because there's no custom name added for "www.leelaurelsgs.com" (web app doesnt know to listen for the domain and subdomain prefix) and the SSL cert you're using also doesnt match
Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-03T13:41:22.1+00:00

Edit

Both Azure front door and Az Traffic manager use Az DNS which supports alias records which also work around the CNAME for apex/root limitation and both can be used in conjunction with a web app (traffic manager would be cheaper but still incur a cost) REF https://learn.microsoft.com/en-us/azure/dns/dns-alias-appservice
leelGS 20 Reputation points

2023-08-03T15:09:20.9833333+00:00
Thanks again...

so what clear simple options are available to me to resolve this? I don't even seem to get the expected response from both leelaurelsgs.com & www.leelaurelsgs.com from my end. - see attached (i was believing changes haven't propagated yet). So do I.....

remove the cname entry? & stick with the A and TXT ones?

getting additional cost (traffic manager) is not on my radar screen now

do I move the domain from Wix to Azure - will this help?

what exactly do I do?

I'd kindly appreciate a clear step-by-step route to resolving this

reading the tutorials & support documents, it looks like a simple task but not so, been on this for some time now

wix2azure.jpg
Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-03T15:33:24.8066667+00:00

it works for me (see snip below)

If I visit the root
What to do?

Depends on your requirements, options
(1)
If you don't want to domain flatten (which you indicate above) and you want users to just reach your site on the root (as per snip above) - then remove the CNAME record for the "www" subdomain with WIX , keep the A record and users can access your site over SSL, but ONLY on the root domain https://leelaurelsgs.com/ (again this is working OK right now)

(2)
If you want to maintain access on the root AND you want to users to be able to visit your site using "www" so "https://www.leelaurelsgs.com" then the CNAME you have already entered is working from a DNS point of view - it's just that web apps isnt recognising the subdomain REF https://learn.microsoft.com/en-us/azure/app-service/app-service-web-tutorial-custom-domain?tabs=subdomain%2Cazurecli#with-a-cname-record

**Note: I would strongly recommend first checking with WIX RE the certificate requirements etc. It doesnt look to me that your cert covers the www subdomain but i could be wrong. I dont know if you got your cert from WIX or somewhere else. Right now your web app isnt answering on "www..." so it's difficult to tell from the outside in
leelGS 20 Reputation points

2023-08-03T18:59:25.6266667+00:00
Thanks again.

I have just verified www.leelaurelsgs.com, updated the DNS records in WIX & added the same to Azure as a custom domain (see attached). Both leelaurelsgs.com and www.leelaurelsgs.com are securely listed in the custom domain listing. (see the attached). I believe this should resolve all the A, CNAMES & TXT records issues - I suppose.

azure5.pdf

On your suggestions above ref (1 & 2), what is the general best practice or standard practice

I am still not able to access the two sites from my browsers (chrome and Edge)...quite strange!!! Please kindly have a look at the attached (the last snip), and kindly help me clarify my comment. I'm just troubleshooting wildly!!!!! as it is quite strange...
leelGS 20 Reputation points

2023-08-03T19:16:22.78+00:00

just to add, I can access the site now. I just can't figure out what went wrong. But still, be grateful if you clarify my comment
Ben Gimblett 4,560 Reputation points Microsoft Employee

2023-08-04T08:30:42.7733333+00:00

I think the additional steps worked out fine - for whatever reason (delay in propagation?) you were not able to see the changes for a while?

Both the apex and www work fine and the SSL is working on both. There appears to be two certs returned (at least from my browser - chrome - perspective) one with the subject for the apex ==> CN = leelaurelsgs.com and one with the subject for the www prefix ==> CN = www.leelaurelsgs.com

What you've now done now is fine. RE the options above, this isnt an Azure or hosting issue per-se it's the way the internet works (re the discussion on the subject I linked in one of the comments above). The advantage of using CNAME (and if you want to use the apex then 'flattening' is the work around avoiding an A record) is that you dont take a direct dependency on the IP address, in this case you take a dependency on the Azure owned domain and we (Azure) manage the last part of the resolution between our domain name and the IP.

Using an A record means you just need to be cognizant of when an IP could change and how to be informed - because you assume at least some users will access your site using the apex/root and not prefix "www."
The details you need to be aware of for that for App Service are here https://learn.microsoft.com/en-us/azure/app-service/ip-address-change-inbound

All good. Glad you got it working
leelGS 20 Reputation points

2023-08-04T21:34:41.6833333+00:00

Thanks a million for your support. Sincerely appreciated.

I guess I will be considering taking down the A record for obvious reasons. Makes sense to me - Business continuity is key here and it will be a hard nut monitoring IP changes if and when they occur.

Again very many thanks

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CNAME record for a verified custom domain

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