I am working on an Azure-based networking solution.
We have a typical hub and spoke VNets topology. The Hub VNet connects to on-prem DC via ExpressRoute and spoke VNets peer to Hub VNet. There is an Azure Firewall in the Hub that filters traffic between Hub-spokes and hub-on-prem segments. GREEN in the diagram
We have a bizarre requirement of adding a new isolated VNet (RED in the diagram) that will have overlapping IPs with the existing network (GREEN). We want to allow workloads in this new VNet to access private apps deployed in Hub or on-prem.
I need help on how to achieve this connectivity.
Note: We don't want to set up any VPN between the new VNet and Hub
As you might appreciate, this is more of a general networking limitation moreso than an Azure limitation. If we want two different networks with overlapping IP addresses to communicate then we would need networking devices in between both networks that perform some form of network address translation so the IP addresses appear to be different to the communicating hosts. Below is an example from the Azure documentation
Logically you have two options here:
Create your own network devices and configure routes between these subnets to transit your virtual appliance that does the translation.
Use the managed service from Azure. In this case, it's the Azure VPN Gateway
I saw your note above for not wanting to use any VPN devices. Having said that, however, generally speaking it is usually a better option from an availability & supportability perspective to leverage the built-in offering vs. hand rolling your own virtual appliance using IP tables or a Windows NAT Router or something similar. Hope this clarifies.
It is not possible to peer Virtual Networks with overlapping IP addresses. This is documented here. You will have to move to a different address space and move/recreate resources under this new address space.
If it helps you can take a look at this Checklist before moving resources.
Related
I was told recently that the Hub VNET is only used in case there is on-premise networking to/from considerations.
I am quite surprised as were many, at the table.
I was under the impression if I have, say, a AZURE Cloud only env. that I could still have a Hub Spoke approach. Or is this not so? What would be the preferred non-Hub Spoke approach if there is peering or inter-VNET access required?
I am aware of VNET Peering and other methods to access resources in other VNETs, API's and Private Link.
The hub-spoke approach works great in some scenarios in cloud-only environments - although in most of docs or architectural patterns Microsoft shows it together with on-prem connectivity.
I used it frequently when we shared some resources like ACR, Log Analytics or simply to host a jump host (with Bastion) to access resources in other networks.
One of the most common scenarios is also the Azure Monitor Private Link Scope, where the hub-spoke topology is recommended:
https://learn.microsoft.com/en-us/azure/azure-monitor/logs/private-link-design#hub-and-spoke-networks
In an Azure Cloud only environment, you can still have a Hub-Spoke approach and this is the recommended one.
While you can cross-peer different spokes to form a Mesh for spokes to exchange data (in a non-Hub scenario), this will become complicated as the number of spokes increases. You will have to configure 1:n Peering in every VNet.
With Hub-Spoke model, you have to route spoke-spoke traffic via Hub Vnet, but the advantage here is that the Hub Vnet becomes the single point entry for the environment and you can deploy resources here that would be shared and used by all other VNets (such as custom DNS server, Firewall)
can anyone explain difference between Azure Application Gateway, Virtual Network Gateway, Virtual WAN, ExpressRoute, Arc and Private Link, please?
It seems to me all services are pretty similar helping with connecting either on-prem to Azure, in-Azure to in-Azure or public to Azure.
They're similar in that they all involve network traffic, but that's pretty much where the similarities end.
Application Gateway is a Layer 7 load balancing service with advanced features like SSL termination. It's used to route client requests to your applications.
Virtual Network Gateway is a VPN gateway for point-to-site (user) and site-to-site (office/datacenter) VPN connections to your own Azure VNETs. This would, for example, allow you to RDP into Azure VMs from your on-prem office using their private IPs.
ExpressRoute is similar to site-to-site, however it doesn't use IpSec tunnels, it's a dedicated, unencrypted connection from your location directly into Microsoft's backbone. (i.e. you don't traverse the public internet). There's no encryption and the connection is faster. This is a service you need to work with a 3rd party internet provider to implement.
Virtual WAN is more like a networking hub where there would be many site-to-site, point-to-site, ExpressRoute, etc... connections spanning a wide area (as the name implies). This would be for large enterpise organizations with many on-prem locations.
Arc is a means of adding your on-prem resources into Azure for management. e.g. you have a physical server somewhere and you want to manage it though ARM/portal.
Azure Private Link is a feature of many Azure services (storage, SQL PaaS, etc..) which allows you to create a private DNS record and assign a private IP address on your internal VNETs. This is used when you want to disable all public network access to a resource and only allow access from within your own VNET.
I have barely scratched the surface of the differences here, but suffice it to say, there are many differences. From this page, you can type the service name into the search and get more specific details on the offering. Hope this helps.
https://learn.microsoft.com/en-us/search/?terms=networking%20in%20azure
Again, I tried to create a VNet-to-VNet connection.
Briefly, I created
Gateway Subnet at East US Region
Gateway Subnet at West US Region
Virtual Network Gateway for East US Region and
Virtual Network Gateway for West US Region
Using Connection type VNet-to-VNet, I connected both Virtual Network Gateway from both sides.
I created connection between both Virtual Network Gateway.
The status of both connections says, Connected.
Windows Server Domain Controller is set up at East US and Windows 10 is installed at West US.
Windows 10 is unable to ping and join the Windows Server Domain Controller.
While joining the Domain Controller, the error message is
The issue is
I am able to connect both VMs which is at two different VNets using RDP with Public IP.
Both VMs’ virtual network gateways are also connected to each other through Connections.
I am able to connect one VM from another using RDP with Private IP.
But I am not able to join Windows 10 VM to Windows Server 2016 Domain Controller.
I request please go through the link https://1drv.ms/u/s!Ail_S1qZOKPmlgBU5fLviInoisrx?e=ImrqpL and help me to fix the issue related to VNet-to-Vnet Connection so that Windows 10 VM from one VNet can join the Windows Server 2016 Domain Controller VM which is at another VNet.
I hope you'll consider it positively.
Regards
TekQ
You might have to create routes, you are not using recommended private address space so routes are not created for you.
Azure automatically creates default routes
for the following address prefixes: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16: Reserved for private use in RFC 1918.
100.64.0.0/10: Reserved in RFC 6598.
Check the effective routes to seen next hop for traffic in the peering address space.
https://learn.microsoft.com/en-us/azure/virtual-network/diagnose-network-routing-problem
Additional Information on VNet Routing
https://learn.microsoft.com/en-us/azure/virtual-network/virtual-networks-udr-overview
Instead of rely on Vnet Gateway and VPN S2S, you could as well using Vnet Peering between region.
https://learn.microsoft.com/en-us/azure/virtual-network/virtual-network-peering-overview
I agree with the other answers. Global VNet Peering would remove the necessity of using a VPN GW, which greatly simplifies the environment and removes the monthly cost of hosting a pair of GWs. Assuming you need those GWs for other connections to VPN devices on-premises, then you can still use this design.
As Hannel pointed out, you're using public ranges for your private networks. That is also okay, but routing would be affected for VMs in those subnets if they attempted to go to actual public IPs in those ranges. Note that Hewlett Packard owns large parts of those ranges, so if your VM needed to get info from an HP website, you would have to create manual UDRs to route that traffic to Next Hop Internet.
So, please do check your Effective Routes on your NICs. You can check this from the NIC and also from Network Watcher. This should help you identify if another route is taking precedence or even if you have a route sending traffic to a virtual appliance.
Do make sure that you chose VNet-to-VNet when you set up your connection. If you chose IPSec, then you would need to have correctly configured your local network gateways.
If two vnets are connected to each other via multiple set of peering vnets, how does azure route the traffic? Fo example, lets consider the below: A, B, C, D are 5 VNets and the they are peered (bi-directionally with traffic forwarding allowed).
Now if A wants to send a packet to D, how it is determined whether it will take the A-B-C-D path or the A-E-D path?
Any docs will be helpful.
As far as I know, VNet Peering connections are non-transitive. It seems that it's still on the roadmap. See the feedback here.
From your picture, If only VNet Peering connections between them, then A could not reach D, also A could not reach C. A only could reach direct-connected B and E.
If you want to allow much VNets communication. You could implement a hub-spoke network topology in Azure. As the hub network, you could deploy a VPN gateway then enable allow gateway transit to other spoke VNets and enable use remote gateways in each spoke VNets. If you require connectivity between spokes, consider implementing an NVA for routing in the hub, and using UDR(custom routes) in the spoke to forward traffic to the hub. In this scenario, you must configure the peering connections to allow forwarded traffic.
VNet Peering enables you to connect VNets through the Azure backbone network. Azure automatically creates a route table for each subnet within an Azure VNet and adds system default routes to the table. You can also override some of Azure's system routes with custom routes.
If multiple routes contain the same address prefix, Azure selects the
route type, based on the following priority:
User-defined
route BGP route
System route
You could get more details about Virtual network traffic routing
According to this article you'd need an NVA somewhere, vnet peering is non transitive.
At the beggining of the same article they talk a bit more about this.
To sum it up. packet wont reach D from A unless you fix your networking setup
Some years ago but i think service chaining allows that as far as i understand the documentation
To enable service chaining, configure user-defined routes that point
to virtual machines in peered virtual networks as the next hop IP
address. User-defined routes could also point to virtual network
gateways to enable service chaining.
Can someone let me know when Microsoft Azure introduced Vnet Peering? I'm working with a company that has introduced a number of Vnets (8 Vnets) for security. I'm trying to suggest that creating that number of Vnets is unnecessary.
I just would like to know if there are any other benefits to Vnet peering and when it was first introduced by Azure?
Cheers
Carlton
I just would like to know if there are any other benefits to Vnet
peering and when it was first introduced by Azure?
Virtual network peering enables you to connect two virtual networks in the same region through the Azure backbone network. Once peered, the two virtual networks appear as one, for connectivity purposes. The two virtual networks are still managed as separate resources, but virtual machines in the peered virtual networks can communicate with each other directly, by using private IP addresses. More information about this please refer to this link.
I'm trying to suggest that creating that number of Vnets is
unnecessary.
It depends on your company's need. If you want to connect two Vnets, you must create a peering tunnel.
VNet peering is between two virtual networks, and there is no derived transitive relationship.
In others words, if you want 3 VNets to be both interconnected, you need create 3 peering tunnels. Please refer to the similar question.
We announced peering in September 2016. See our service update for reference: https://azure.microsoft.com/en-us/updates/vnet-peering-ga/
VNet peering has many benefits: low latency, high bandwidth, direct VM to VM connectivity among others. You can see a comprehensive list here: https://learn.microsoft.com/en-us/azure/virtual-network/virtual-network-peering-overview
You can also suggest using subnets in the same virtual network: https://learn.microsoft.com/en-us/azure/virtual-network/virtual-networks-create-vnet-arm-pportal
-- Anavi N [MSFT]