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We made no changes this morning to our staging, demo or production apps and they all started failing when trying to connect to signalr server. In production the error was "No such host is known". this is in canada central. i login to one of our prod servers in kudu / console and i can get correct nameresolver results back back for our azure assigned server name, (and for microsoft.com) but not for the dns we have assigned to the server. i have confirmed our dns is up to date and nslookups from my workstation all work fine.
The fact that this started happening, after all services were working fine this morning, and they all broke at once, across multiple azure subscriptions all in central canada makes me think it is an azure issue. Please help!
An Azure service that enables hosting Domain Name System (DNS) domains in Azure.
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Hi Bruce Holman,
Thank you for reaching out in Microsoft Q&A forum,
after all services were working fine this morning, and they all broke at once, across multiple azure subscriptions all in central canada makes me think it is an azure issue. Please help!
The simultaneous failure across your staging, demo, and production environments in Azure Canada Central manifesting as "No such host is known" errors for SignalR connections indicates a DNS resolution issue within Azure's infrastructure, rather than an application-level problem.
Verify the below steps:
Execute these commands immediately in the Kudu console:
nslookup <your-signalr-domain.com> 168.63.129.16
nslookup <your-signalr-domain.com> 8.8.8.8
Failure on Azure's recursive resolver (168.63.129.16) while Google DNS (8.8.8.8) succeeds confirms internal resolver caching or propagation delay.
Try the below steps:
<resource-name>.service.signalr.net), bypassing custom DNS entirely.Reference:
Kindly let us know if the above helps or you need further assistance on this issue.
Please “up-vote” wherever the information provided helps you, this can be beneficial to other community members.
Yes we are already changing our config to use native host names... It is concerning as this has been working for 1/2 year no problem. This caused an outage for our customers.
Hi Bruce,
Azure status page shows no active incidents in Canada Central right now (status.azure.com) everything green for DNS, App Service, SignalR.
Could you please share the kudu console nslookup output in Private message? Have you facing the issue still?
azure status page never showed an issue, yet we had one. Thank you for the help with this today! :)
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I can confirm Azure had DNS issues on March 16th. Our production and staging Azure app services couldn't connect to other services in Azure. Started around noon Central and lasted for hours. Even tried scaling up/down for that extra hard reset with no luck.
I went to test again and it is now all working as expected. nslookups and nameresolver queries against our named server name are returning correct responses now.