I've got an Azure Virtual Network setup and a VM setup within the network. I've installed the Hybrid Connection Manager app on the VM.
I also have an Azure App Service and I've created a hybrid connection between it and the VM and they are both claiming they are happily connected to each other.
Also on the VM I've installed an app that is listening on http://localhost:1234
Can someone tell me what IP I use from my app service to talk to http://localhost:1234 on the VM? e.g. Is it [VM internal IP]:1234 or [VM public IP]:1234, or something else. Nothing is talking at the moment so I want to make sure the IP address is not the problem.
Just use the computer name of the VM. For example, call to SQLSRV009:1234 from your code in App Service. The Hybrid Connection definition in the portal should reflect the same name (same as computer name, same as what you're calling from your code).
Check out this well written guide for the full picture —
https://learn.microsoft.com/en-us/azure/biztalk-services/integration-hybrid-connection-create-manage
It is possible to set a Hybrid Connection endpoint to an IP address. If you use an IP address, you may or may not reach the on-premises resource, depending on your client.
The Hybrid Connection depends on the client doing a DNS lookup. In most cases, the client is your application code. If the client does not perform a DNS lookup, (it does not try to resolve the IP address as if it were a domain name (x.x.x.x)), then traffic is not sent through the Hybrid Connection.
For example (pseudocode), you define 10.4.5.6 as your on-premises host:
The following scenario works:
Application code -> GetHostByName("10.4.5.6") -> Resolves to 127.0.0.3 -> Connect("127.0.0.3") -> Hybrid Connection -> on-prem host
The following scenario doesn't work:
Application code -> Connect("10.4.5.6") -> ?? -> No route to host
Also make your app listen on either 0.0.0.0 or the private IP since i'm not terribly sure localhost will work with HC.
Why not use VNET integration for the Web App? All you need to do is create a route based (IKEv2) VPN gateway in the VNET, like so —
https://learn.microsoft.com/en-us/azure/app-service/web-sites-integrate-with-vnet
You should use VM host name, thanks for evilSnobu's link .
If you use an IP address, you may or may not reach the on-premises
resource, depending on your client.
If you use VM public IP, traffic packets are transmitted over the Internet to your VM not VPN tunnel. localhost only could be used inside VM.
Also, if your app is listening on localhost(127.0.0.1), the service only could access inside your VM. As evilSnobu said, you need modify your service listening on 0.0.0.0 or private IP(like 10.0.0.4). You could check with following command.
For Linux
netstat -ant|grep 1234
For Windows
netstat -ant|findstr 1234
Related
I'm experiencing some deeply frustrating issues when trying to connect to a SQL server Private Endpoint. Setting aside for a moment a complete specification of the problem, I'd like answers to the following questions
Is it the case that a SQL Server Private Endpoint will only listen to connections from an Azure Virtual Machine? I have seen it suggested by 3rd parties that this is the case but cannot find this explicitly documented by MS. (To clarify, if only VMs can connect, then this would mean, for example, that an Azure Load Balancer could not use Private Endpoint as a backend resource; and, for example, that an on-premise VM could not connect to a Private Endpoint through a VPN - is that correct?)
Presuming the answer to the above question is Yes, then does the restriction apply such as to prevent Private Endpoint from listening to connections forwarded from an Azure VM interface?
(For example, say a firewall in a VM in Azure. Inside the firewall VM, the IP 192.168.0.10 is configured. In Azure, the VM interface is associated with only a single IP address which is IP 192.168.0.6. In this scenario, the firewall VM will respond to ARP requests with ARP responses saying "I have 192.168.0.10", but 192.168.0.10 is not associated by Azure configuration with any Azure virtual network interface. In said case, will a connection to the Private Endpoint using source address 192.168.0.10 work? Or is it the case that the PE will listen for connections only with a source address 192.168.0.6?)
To answer your questions:
It's possible that use a private endpoint as backends in the Azure Load balancer because Azure LB supports NIC or IP address as the backend target. Also, the on-premise VM surely can connect to a private endpoint through VPN tunneling, read this document for more details.
A VM by default sends all outbound traffic to the IP address that's assigned to the primary IP configuration of the primary network interface. So it will use source address 192.168.0.6 when connecting to the private endpoint. Read the network interface constraints.
Here a Data engineer who needs your help to setup a connection to an on-premise environment :)!
I have created a virtual network (10.0.0.0/16) with a default subnet (10.0.0.0/24).
Then I created a (Windows) virtual machine which is connected to the vnet/subnet and has allowed ICMP inbound and outbound rules for the ping test. Ping google.com is no problem.
The next step was to create a Virtual network gateway & Local network gateway to connect to an on-premise environment.
The Local network gateway has an Site-to-site (IPsec) connection to a VPN device from a third party (over which I have no control). Status in the Azure portal = 'Connected'.
The third party is able to ping the Virtual Machine in Azure, the 'data in' property on the VPN connection shows that 2 kb (ping) has been received. So that works!
When i try to send a ping command to the ip-address (within the 'address space' specified from the Local network gateway) the ping command fails (Request timed out.).
After a lot of searching on google/stackoverflow I found out that I need to configure a Route Table in Azure because of the BGP = disabled setting. So hopefully I did a good job configure the Routing Table Routes but still I can't perform a successful ping :(!
Do you guys/girls know which step/configuration I have forgotten or where I made a mistake?
I would like to understand why I cannot perform a successful ping to the on-premise environment. If you need more information, please let me know
Site-to-site (IPsec) connection screenshot/config
Routing Table setup screenshot/config
Routing Table Routes in more detail
If you are NOT using BGP between the Azure VPN gateway and this particular network, you must provide a list of valid address prefixes for the Address space in your local network gateway. The address prefixes you specify are the prefixes located on your on-premises network.
In this case, it looks like you have added the address prefixes. Make sure that the ranges you specify here do not overlap with ranges of other networks that you want to connect to. Azure will route the address range that you specify to the on-premises VPN device IP address. There are no other operations that we can do. We don't need to set UDR, especially we don't associate a route table to the Gateway Subnet. Also, avoid associating a network security group (NSG) to the Gateway Subnet. You can check the route table by selecting Effective routes for a network interface in Azure VM. Read more details here.
If you would like to verify the connection from Azure VNet to an on-premise network, ensure that you PING a real private IP address from your on-premise network(I mean the IP address is assigned to an on-premise machine), you can check the IP address with ipconfig/all in local CMD. Moreover, you could Enable ICMP through the Windows firewall inside the Azure VM with the PowerShell command New-NetFirewallRule –DisplayName "Allow ICMPv4-In" –Protocol ICMPv4. Or, instead of using PING, you can use the PowerShell command Test-NetConnection to test a connection to a remote host.
If the problem persists, you could try to reset the Azure VPN gateway and reset the tunnel from the on-premises VPN device. To go further, you could follow these steps to identify the cause of the problem.
So I'm using an Azure VM that has a public IP address, and I've opened an inbound port, let's say it's 5555.
What I'm trying to do now is to run an application on the VM that has an API via localhost, also with the port 5555. I'm calling it then with public_ip:5555/api/...
Since I was not able to connect to the application from outside, is there something missing here? Most tutorials and resources I've found just mentioned opening the port.
Thanks.
Take a look at Azure's IP Flow Verify utility, which will check your NSG rules to ensure traffic can reach your VM. https://learn.microsoft.com/en-us/azure/network-watcher/network-watcher-ip-flow-verify-overview
If traffic is reaching your VM, check your host firewall and then your application server logs.
I'm new to Azure (strike 1) and totally suck at networking (strike 2).
Nevertheless, I've got two VMs up and running in the same virtual network; one will act as a web server and the other will act as a SQL database server.
While I can see that their internal IP addresses are both in the same network I'm unable to verify that the machines can communicate with each other and am sort of confused regarding the appropriate place to address this.
Microsoft's own documentation says
All virtual machines that you create in Windows Azure can
automatically communicate using a private network channel with other
virtual machines in the same cloud service or virtual network.
However, you need to add an endpoint to a machine for other resources
on the Internet or other virtual networks to communicate with it. You
can associate specific ports and a protocol to endpoints. Resources
can connect to an endpoint by using a protocol of TCP or UDP. The TCP
protocol includes HTTP and HTTPS communication.
So why can't the machines at least ping each other via internal IPs? Is it Windows Firewall getting in the way? I'm starting to wonder if I've chose the wrong approach for a simple web server/database server setup. Please forgive my ignorance. Any help would be greatly appreciated.
If both the machines are in the same Virtual Network, then just turn off Windows Firewall and they will be able to ping each other. Other way is to just allow all incoming ICMP traffic in Windows Firewall with Advanced Settings.
However there is a trick. Both the machines will see each other by IP Addresses, but there will be no name resolution in so defined Virtual Network. Meaning that you won't be able to ping by name, but only by direct IP address. So, if want your Website (on VM1) to connect to SQL Server (on VM2), you have to address it by full IP Address, not machine name.
The only way to make name resolution within a Virtual Network is to use a dedicated DNS server, which you maintain and configure on-premises.
This article describes in details name resolution scenarios in Windows Azure. Your particular case is this:
Name resolution between virtual machines and role instances located in
the same virtual network, but different cloud services
You could potentially achieve name resolution, if you put your VMs is same cloud service. Thus you will not even require dedicated virtual network.
If your VMs are inside a Virtual Network in Azure, then you have to make sure two things.
Required Port is enabled.
Firewall is disabled on the server.
I was trying to connect to one VM where SQL Server DB was installed, from another VM. I Had to enable 1433 port in the VM where SQL was installed. For this you need to add an MSSQL endpoint to the VM on the azure management portal. After that i disabled windows firewall. Then i was able to connect to the VM from another.
I would like to host a firebird database in an Azure virtual machine.
Normally, I would indicate in a program a connection like this:
hostname:databasename
....to connect to remote host. In azure, you cannot do that.
I would need to connect with something like:
?.cloudapp.net:someport:databasename
The client would be talking to ?.cloudapp.net thinking that someport is the port to communicate with the database server.
So it seems I would need a proxy to login-connect to windows azure cloud resources and the client would then use the proxy to talk with the database server. This looks like a hassle - are there any alternatives?
I'm not entirely sure of your Cloud architecture in Azure, but assuming you have one VM with your DB installed you should be able to open up a a public endpoint (via the portal manage.windowsazure.com for your Cloud Service) and connect to that via it's public IP address & the port).
Windows Azure does have more advanced features that allows you to connect to specific VM's within a Cloud Service via Port Forwarding.
Michael Washam has a great blog post on this 'Windows Azure Virtual Machines':
http://michaelwasham.com/2012/06/08/understanding-windows-azure-virtual-machines/
The architecture of cloud services makes endpoint configuration
interesting. Since each cloud service has a single public IP address
but multiple virtual machines can reside in it how do you address
individual servers directly in a non-load balanced fashion?
Port forwarding allows you to configure an endpoint on a specific VM
listening on any of the ephemeral ports that will then be forwarded to
the correct internal port.