Lastly, let's troubleshoot Azure VM connection issues. Now,
what if you're experiencing client connectivity issues to your Azure VMs?
These client connections could be administrative connections where you
want to come in on remote desktop protocol TCP port 3389.
If it's a Linux VM, or, let's face it,
you may want to do SSH on Windows Server as well,
then your management port is going to be TCP 22 by default. But those
connections can also be pure client connections from other servers, from
client devices who need to consume resources on the server, etc. Here are
some tools that you can turn to in Azure. Network Watcher is an entire
basket load of troubleshooting tools principally for virtual networking.
In the context of an Azure VM, we can access connection troubleshoot to
get a deeper idea of why that client connection can't reach the VM.
If we think maybe it's network security group‑related,
maybe there's a security rule that's getting in the way, after all, Azure VMs
can have NSG protection at two scopes, at the network interface scope, as
well as the virtual network subnet scope, there are a couple of tools in
Network Watcher for that. Particularly, there's NSG Diagnostic. In the
context of Azure Resource Manager in the VM, there's a convenience that
Microsoft gives us. It's basically a collection of scripts called run
commands where you can do, say, an ipconfig, you can get RDP client settings,
just enables you to get some metadata from a VM that may
otherwise be inaccessible under your normal means.
Could be a routing issue,
particularly if you're implementing user‑defined routes in your virtual
networks. There we've got Network Watcher Next Hop. And then last, but
not least, never forget the host firewall.
I don't know how many times I've worked with customers and clients and students,
all of the above, and in troubleshooting Azure VM connectivity,
we crossed out all of the other tools.
Everything was looking good.
And then I asked, almost as an aside, well,
what about Windows Defender Firewall, or, Linux, what about UFW? And then
it's, oh, okay, yeah. Never forget about the host firewall that's running
in the guest OS environment of those Azure VMs. Now let's get to our demo.