I have the following situation:
If I deploy an application (Deployment, Service and Ingress) in my kubernetes cluster, my ingress deployment is being automatically added to my application gateway (I am using the Azure Application Gateway Ingress Controller; https://azure.github.io/application-gateway-kubernetes-ingress/annotations/ ). So far so good.
That means that my application can be reached via my application gateway via https://my-app-gateway-public-ip/myAppPath/. Also, I have an additional private DNS zone which makes my app accessible via https://dns-name/myAppPath.
Additionally, we have an AADDS in combination with a Bastion Service. Deployed some virtual machines and the virtual machines use the DNS resolver of the AADDS (for authentication against the AAD).
The problem is: If I am outside of the cloud, I can nslookup the dns or can access the site via the ip, but I cannot do that with my virtual machines. My DNS server (within the AADDS) is unable to resolve the dns or accessing the ip. I am wondering what the issue is.
The bastion and AADDS are in different subscriptions and therefore different virtual networks. I established already a peering between those virtual networks (or the authentication between the AADDS and the VMs wouldn't work).
The kubernetes cluster and the application gateway are also in a different subscription, but no peering has been done so far.
Are there any hints what I could be missing?
Kind regards
• Since, you are using a Bastion gateway server to connect to the VMs hosted in your subscription, the Bastion gateway server must be having a public IP address through which then the registered underlying VMs can be connected to via private links created in the private DNS zones associated with a particular virtual network in a subnet and an assigned private IP address and a FQDN accordingly. Thus, if you want to access the application website hosted behind the application gateway, then you will have to create a conditional forwarder in the DNS zone in AADDS to redirect the internal requests from the VMs hosted within a virtual network to the public IP address of the website hosted behind the application gateway
• Thus, a conditional forwarder forwards the DNS resolution requests for a particular resource hosted on the public internet for which the DNS host resolution is not found or done in that DNS zone which usually serves or fulfils the requests related to internal environment. As a result, when a VM configured with a private IP is registered as a host in the internal DNS zone queries the public IP or FQDN associated with the application’s website, the DNS requests are forwarded to the public internet through the conditional forwarder and then the results are displayed in the VM’s browser for the application’s webpage. Thus, the VMs don’t need to have internet access but the DNS server should have or should forward the requests through the Internet proxy server accordingly to reach the internet.
For more information on creating conditional forwarder in AADDS, kindly refer to the below link: -
https://learn.microsoft.com/en-us/azure/active-directory-domain-services/manage-dns#create-conditional-forwarders
Related
I configured the private DNS zone so that the client Virtual machine( which I created in it) can connect to the webserver( Which I created in Azure with loadbalancer ).I also did the network peering between vnet 1 and vnet2 which are private. vnet 1 is for webserver 1 and webserver2( I created this virtual machine and did virtual peering with webserver1).
After login to client I am trying to reach website mst300-lb.harmandeep14.com
mst300lb is my load balancer name
harmandeepkaur14.com is my privated dns zone name
I created the feature iis in webserver 1 and webserver2
I want to reach mst300-lb.harmandeep14.com in client but I cannot
where I am going wrong?
enter image description here
What should I do view this website on client virtual machine.
enter image description here
This is load ip address.
and that's the record I created in loadbalancer.
enter image description here
• From what you have configured the environment, I can understand that you have configured the two webservers in the same virtual network, i.e., VNET1 and the client VM from where you are accessing the IIS webpage hosted on the webservers is hosted in virtual network 2, i.e., VNET2 and you have configured peering between them so that the client VM can access the IIS webpage hosted on the webserver pool configured as a backend in the load balancer.
Thus, you will have to create a CNAME record in your private DNS zone for the load balancer name with the alias as the actual name of the IIS webpage/website hosted on the servers as shown below in the snapshot: -
• Once you create a CNAME record for the IIS webpage in your private DNS zone with the alias as the FQDN of the load balancer, ensure that an ‘A’ host record also exists for the load balancer such that the CNAME record can track and resolve the load balancer from here itself. Also do ensure that you have configured virtual network links with both the virtual networks as shown below in the snapshot for webservers and client VMs to be added in here.
Since, you are using private DNS zone, I would also recommend you create ‘A’ host records for both the webservers as well as client VMs, this will ensure that for your private network, every resource is registered in the appropriate DNS zone and the request for accessing the webpage is routed correctly to the backend resources. Also, ensure that the webpage/website application hosted on the webservers also have an ‘A’ host record in the private DNS zone created which will in effect load balance the traffic received on the frontend to the backend webservers and the webpages/websites hosted on them.
Also, do ensure that the website if hosted internally on port 80 TCP HTTP, then ensure that the health probe is configured accordingly in the load balancer rules for the traffic over HTTP port 80 to be routed and load balanced further to the backend pools.
I'm migrating asp.net services that used to exist on a physical server on-premise to Azure. However they need to reach some web-services (SOAP) that will not be migrated to azure yet. These have a public IP but I need to set the hostname in order for IIS to properly redirect the requests to the correct service as there are several on the same server. Is there any way to create some sort of DNS-server in azure that is only available for the services created in azure that can resolve to the public IP-address outside of azure? (We have used the hosts file on the servers to achieve this previously)
I tried using the private DNS Zones, but as I've understood it they can only point to other azure services within the same vnet (correct me if I'm wrong). I've also tried creating a dnsmasq docker container. However, as this is running in a Linux container, it seems that I cannot put it in the same vnet as the asp.net app services. Thus I am unable to retrieve a private IP-address that these services can use to reach the DNS server.
In my understanding it is now possible to use Azure DNS Private Zones if you want.
You would need to use regional vnet integration to point your app's traffic to a vnet that is connected to the Private Zone. You need the following settings as well, which mean that all outbound traffic from the Web App is routed through the integrated vnet first, and that the Azure default DNS server is used for DNS.
WEBSITE_DNS_SERVER with value 168.63.129.16
WEBSITE_VNET_ROUTE_ALL with value 1
https://learn.microsoft.com/en-us/azure/app-service/web-sites-integrate-with-vnet#azure-dns-private-zones
If you don't want to use Azure DNS Private Zones, I think you can achieve similar results by directing the Web App to use a specific DNS server. This can be done using WEBSITE_DNS_SERVER and WEBSITE_DNS_ALT_SERVER app settings (the values are the IP addresses of the servers you want to use).
This is the most authoritative public statement I can find about using these settings.
Go to the web app->settings->Application Settings-> App Settings
section
Add the following: (WEBSITE_NODE_DEFAULT) should already be
there.
a. WEBSITE_DNS_SERVER with value having the IP address of the
primary DNS server.
b. WEBSITE_ALT_DNS_SERVER (optional), with value
having the IP address of a second DNS server.
Then save the settings & restart webapp in portal.
Double check the web app can actually
connect to the DNS server: a. In kudu console, run: Nameresolver.exe
[hostname-to-lookup] [dns-server-to-use]
First argument should be the
hostname you are trying to look up, second argument is one of the DNS
servers from step 1) If this times out, there is an issue with how
your DNS servers are configured (firewalls, etc.)
https://github.com/MicrosoftDocs/azure-docs/issues/13927#issuecomment-416382230
If using these settings with a DNS server that is only accessible via private IP, you would need to use regional vnet integration again to connect to a vnet. If the DNS server is on-prem, you have to connect through the integrated vnet over VPN or ExpressRoute.
It's possible but not using the private DNS Zone.
According to Name resolution for resources in Azure virtual networks. For the scenario Name resolution from App Service Web Apps in one virtual network to VMs in a different virtual network, you need to use your own DNS servers forwarding queries between virtual networks for resolution by Azure (DNS proxy). See Name resolution using your own DNS server.
In this case, you only allow this azure web service could resolve the public IP address outside of Azure. You could enable virtual network integration for your web app, this restricts your web app access in a private network. Then you could deploy a DNS server in the same Vnet as the web app integrated VNet. You could create an A type record in your DNS zone to point to your service Public IP, then add the DNS server's IP address into the DNS server of the Integrated web app Vnet in the portal. If so, the web app could resolve this public IP via a custom DNS server.
Hope this could help you.
VM and App Service are located in the same Virtual Network.
App Service is added to VM through VNet Integration (preview)
VM is autoregistered in Private DNS zone, say by name myvm1. And full name myvm1.priv.zone
Private DNS zone is linked to Virtual Network.
Virtual Network - DNS Servers is set to default.
VM and App Service were restarted after configuration.
Problem is I can resolve neither myvm1 nor myvm1.priv.zone from App Service console by nameresolver.exe
UPDATE:
Actually, the issue is even bigger. App Service is not able to send requests to VMs in Virtual Network by their Private IPs (10.1.x.x) even if everything is allowed on VMs' subnet. If the same requests are sent to VMs' Public IPs there is no problem.
As the existing answer, for scenario Name resolution from App Service Web Apps to VMs in the same virtual network. in this DOC, you need to deploy your own DNS server to help name resolution.
Here are the steps:
On the Azure VM in the VNet, add a server role DNS server, after the installation, configure the DNS server, add Zone name such as qaz.lab in my example. You also can manually add an A record for your Azure VM in this Zone.
Add the DNS server private IP address in the custom DNS server of Azure VNet. Then restart the Azure VM to make it effective.
Configure VNet Integration with your app, in this case, select the new VNet integration. After that, refresh your VNet Integration. You will see the DNS server update in your app service plan --- networking.
Navigate your app service, run nameresolver FQDN to validate the DNS resolution. Currently, It only supports FQDN resolution.
Let me know if you have any question.
As of today, you need to use DNS proxies or forwarders to achieve your ask. It is documented here in the scenario table.
For scenario "Name resolution from App Service Web Apps to VMs in the same virtual network.", the solution is to "Customer-managed DNS servers forwarding queries between virtual networks for resolution by Azure (DNS proxy)."
On How to perform "Name resolution with your own DNS" check here, where your scenario is described.
I followed the documentation guide here to configure an Azure DNS zone for a virtual network.
I then created a virtual machine on that virtual network and provisioned a virtual network gateway to allow my Azure web apps to communicate with the virtual machine using VNet integration. My web apps are then able to resolve against the virtual machines private IP as expected.
I then created an 'A' type record set within the DNS zone resolving a service name against the private IP of the virtual machine just like here.
However, when I then attempt to access the DNS configured service name that should resolve against the private IP address of the virtual machine, I get the following error:
curl: (6) Could not resolve host: xxxx.local
Am I missing something obvious here?
I can not reproduce this error following your steps:
Create an Azure VNet with a DNS private zone like private.test.com.
Create a VM and a VPN gateway on that VNet.
Enable VNet integration with my Azure web app service.
My web apps are able to resolve against the virtual machines private IP as expected. This could verify the Azure private DNS zone should work. Then I also create an A record for a custom name against the VM private IP address. Both scenarios work.
You could check if an A record is something like below picture in the private DNS zone.
Then you could verify if curl with http:// or without that, or without the specific port 9200, the error is still the same.
I suggest using SET WEBSITE_DNS_ command. This command will output the current DNS server that is being used by the web app. If the error Environment variable WEBSITE_DNS_ not defined is received, no custom DNS servers are configured for the web app. See more details about networking Related Commands for Azure App Services.
I had a need to add additional public IP addresses to an Azure VM and found a working solution here:
Azure VM: More than one Public IP
Essentially this creates a reserved IP in Azure and then adds the reserved IP to a cloud service. Once it's bound to a cloud service it can be mapped to a VM endpoint.
This all works great but there is one bit I don't understand - The IP address of the reserved IP and the resultant VM endpoint don't match. I have to set up DNS to point to the IP address of the endpoint to make this work. Is there something I am not doing right, or is this just the way reserved VMs work?
It looks like this unanswered question is the same issue:
azure reserved IP for VM is diffrent than the given
Thanks!
The "Azure Cloud Service" is a container that provides internet connectivity to "Azure VMs". Thus, you assign the Internet facing Public IP to the Cloud Service. This article is relatively good at explaining the relationship: Azure Cloud Services
From above link:
Here’s a definition of an Azure IaaS cloud service that will make it easy for you to understand what it is in the context of Azure Infrastructure Services:
A cloud service is a network container where you can place virtual machines.
All virtual machines in that container can communicate with each other directly through Azure (and therefore don’t have to go out to the Internet to communicate with each other).
This container is also assigned a DNS name that is reachable from the Internet.
A rudimentary DNS server is created and can provide name resolution for all virtual machines within the same cloud service container (note that name resolution provided by the DNS server is only available to the virtual machines that are located within the cloud service).
One or more Virtual IP Addresses (VIPs) are assigned to the container and these IP addresses can be used to allow inbound connections from the Internet to the virtual machines.
Certain services (like FTP) may require your vm have a public IP: Azure VM Public IP
(IaaS v1) An Azure cloud service comes with a permanent DNS name - something.cloudapp.net - and has a single VIP allocated whenever there are VMs deployed in it OR whenever a reserved IP address is associated with it. Traffic is either load balanced or NATted (port forwarded) to the VM from the Azure Load Balancer sitting on the VIP. You can also associate a public instance-level IP address (PIP) with a VM, which gives it an additional IP address. The VIP always has a DNS name (something.cloudapp.net) while the PIP has one only if you specifically add it, I did a post which goes into these differences.
(IaaS v2) VMs are not deployed into cloud services and only have a public IP address if one is specifically added - either by configuring a PIP on the NIC of the VM (and optionally giving it a cloudapp.azure.com DNS name) or by configuring a load balancer and either load balancing or NATting traffic to it. This load balancer is configured with a public IP address and can optionally have a cloudapp.azure.com DNS name associated with it. (Ignoring internal load balancers in this discussion.)