Single-region deployment with out World Attain, utilizing Safe Digital WAN Hub with Routing-Intent

This text describes one of the best practices for connectivity and visitors flows with single-region Azure VMware Resolution when utilizing Azure Safe Digital WAN with Routing Intent. You study the design particulars of utilizing Safe Digital WAN with Routing-Intent with out World Attain. This text breaks down Digital WAN with Routing Intent topology from the angle of an Azure VMware Resolution non-public cloud, on-premises websites, and Azure native. The implementation and configuration of Safe Digital WAN with Routing Intent are past the scope and are not mentioned on this doc.

In areas with out World Attain assist or with a safety requirement to examine visitors between Azure VMware Resolution and on-premises on the hub firewall, a assist ticket should be opened to allow ExpressRoute to ExpressRoute transitivity. ExpressRoute to ExpressRoute transitivity is not supported by default with Digital WAN. – see Transit connectivity between ExpressRoute circuits with routing intent 

Safe Digital WAN with Routing Intent is simply supported with Digital WAN Normal SKU. Safe Digital WAN with Routing Intent supplies the aptitude to ship all Web visitors and Personal community visitors (RFC 1918) to a safety resolution like Azure Firewall, a third-party Community Digital Equipment (NVA), or SaaS resolution. Within the situation, we have now a community topology that spans a single area. There’s one Digital WAN with a single hub positioned within the Area. The Hub has its personal occasion of an Azure Firewall deployed, primarily making it a Safe Digital WAN Hub. Having a Safe Digital WAN hub is a technical prerequisite to Routing Intent. The Safe Digital WAN Hub has Routing Intent enabled.

The one area additionally has an Azure VMware Resolution Personal Cloud and an Azure Digital Community. There’s additionally an on-premises website connecting to the area, which we overview in additional element later on this doc.

The next sections cowl visitors flows and connectivity for Azure VMware Resolution, on-premises, Azure Digital Networks, and the Web.

This part focuses on solely the Azure VMware Resolution non-public cloud. The Azure VMware Resolution non-public cloud has an ExpressRoute connection to the hub (connections labeled as “D”).

With ExpressRoute to ExpressRoute transitivity enabled on the Safe Hub and Routing-Intent enabled, the Safe Hub sends the default RFC 1918 addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to Azure VMware Resolution over connection “D”. Along with the default RFC 1918 addresses, Azure VMware Resolution learns extra particular routes from Azure Digital Networks and Department Networks (S2S VPN, P2S VPN, SDWAN) which might be related to the hub. Azure VMware Resolution does not study particular routes from on-premises networks. For routing visitors again to on-premises networks, it makes use of the default RFC 1918 addresses that it realized from connection “D”. This visitors transits by means of the Hub firewall, as proven within the diagram. The Hub firewall has the precise routes for on-premises networks and routes visitors towards the vacation spot over connection “E”. Visitors from Azure VMware Resolution, heading in the direction of Digital Networks, will transit the Hub firewall. For extra data, see the visitors circulate part.

The diagram illustrates visitors flows from the angle of the Azure VMware Resolution Personal Cloud.

Visitors Circulation Chart

This part focuses solely on the on-premises website. As proven within the diagram, the on-premises website has an ExpressRoute connection to the hub (connection labeled as “E”).

With ExpressRoute to ExpressRoute transitivity enabled on the Safe Hub and Routing-Intent enabled, the Safe Hub sends the default RFC 1918 addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to on-premises over connection “E”. Along with the default RFC 1918 addresses, on-premises learns extra particular routes from Azure Digital Networks and Department Networks (S2S VPN, P2S VPN, SDWAN) which might be related to the hub. On-premises does not study particular routes from Azure VMware Resolution networks. For routing visitors again to Azure VMware Resolution networks, it makes use of the default RFC 1918 addresses that it realized from connection “E”. This visitors transits by means of the Hub firewall, as proven within the diagram. The Hub firewall has the precise routes for Azure VMware Resolution networks and routes visitors towards the vacation spot over connection “D”. Visitors from on-premises, heading in the direction of Digital Networks, will transit the Hub firewall. For extra data, see the visitors circulate part for extra detailed data.

As talked about earlier, if you allow ExpressRoute to ExpressRoute transitivity on the Hub, it sends the default RFC 1918 addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to your on-premises community. Subsequently, you should not promote the precise RFC 1918 prefixes (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) again to Azure. Promoting the identical precise routes creates routing issues inside Azure. As an alternative, it is best to promote extra particular routes again to Azure to your on-premises networks.

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When you’re presently promoting the default RFC 1918 addresses from on-premises to Azure and want to proceed this follow, it’s worthwhile to break up every RFC 1918 vary into two equal sub-ranges and promote these sub-ranges again to Azure. The sub-ranges are 10.0.0.0/9, 10.128.0.0/9, 172.16.0.0/13, 172.24.0.0/13, 192.168.0.0/17, and 192.168.128.0/17.

The diagram illustrates visitors flows from the angle of on-premises.

Visitors Circulation Chart

This part focuses solely on connectivity from an Azure Digital Community perspective. As depicted within the diagram, the Digital Community has a Digital Community peering on to the hub.

The diagram illustrates how all Azure native assets within the Digital Community study routes beneath their “Efficient Routes”. A Safe Hub with Routing Intent enabled all the time sends the default RFC 1918 addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to peered Digital Networks. Azure native assets within the Digital Community do not study particular routes from exterior of their Digital Community. With Routing Intent enabled, all assets within the Digital Community presently possess the default RFC 1918 deal with and use the hub firewall as the following hop. All visitors ingressing and egressing the Digital Networks will all the time transit the Hub Firewall. For extra data, see the visitors circulate part for extra detailed data.

The diagram illustrates visitors flows from an Azure Digital Community perspective.

Visitors Circulation Chart

This part focuses solely on how web connectivity is offered for Azure native assets in Digital Networks and Azure VMware Resolution Personal Clouds in a single area. There are a number of choices to supply web connectivity to Azure VMware Resolution. – see Web Entry Ideas for Azure VMware Resolution 

Choice 1: Web Service hosted in Azure
Choice 2: VMware Resolution Managed SNAT
Choice 3: Azure Public IPv4 deal with to NSX-T Information Middle Edge

Though you need to use all three choices with Single Area Safe Digital WAN with Routing Intent, “Choice 1: Web Service hosted in Azure” is the best choice when utilizing Safe Digital WAN with Routing Intent and is the choice that’s used to supply web connectivity within the situation. The explanation why “Choice 1” is taken into account the best choice with Safe Digital WAN is because of its ease of safety inspection, deployment, and manageability.

As talked about earlier, if you allow Routing Intent on the Safe Hub, it advertises RFC 1918 to all peered Digital Networks. Nonetheless, it’s also possible to promote a default route 0.0.0.0/0 for web connectivity to downstream assets. With Routing Intent, you’ll be able to select to generate a default route from the hub firewall. This default route is marketed to your Digital Community and to Azure VMware Resolution. This part is damaged into two sections, one which explains web connectivity from an Azure VMware Resolution perspective and one other from the Digital Community perspective.

When Routing Intent is enabled for web visitors, the default habits of the Safe Digital WAN Hub is to not promote the default route throughout ExpressRoute circuits. To make sure the default route is propagated to the Azure VMware Resolution from the Azure Digital WAN, you need to allow default route propagation in your Azure VMware Resolution ExpressRoute circuits – see To promote default route 0.0.0.0/0 to endpoints. As soon as adjustments are full, the default route 0.0.0.0/0 is then marketed by way of connection “D” from the hub. It’s essential to notice that this setting should not be enabled for on-premises ExpressRoute circuits. As a greatest follow, it is really useful to implement a BGP Filter in your on-premises tools. A BGP Filter in place prevents the inadvertent studying of the default route, provides an additional layer of precaution, and ensures that on-premises web connectivity is not impacted.

When Routing Intent for web entry is enabled, the default route generated from the Safe Digital WAN Hub is robotically marketed to the hub-peered Digital Community connections. You may discover beneath Efficient Routes for the Digital Machines’ NICs within the Digital Community that the 0.0.0.0/0 subsequent hop is the hub firewall.

For extra data, see the visitors circulate part.

The diagram illustrates visitors flows from a Digital Community and Azure VMware Resolution perspective.

Visitors Circulation Chart

HCX Mobility Optimized Networking (MON) is an non-obligatory characteristic to allow when utilizing HCX Community Extensions (NE). Mobility Optimized Networking (MON) supplies optimum visitors routing beneath sure eventualities to stop community tromboning between the on-premises-based and cloud-based assets on prolonged networks.

Enabling Mobility Optimized Networking (MON) for a selected prolonged community and a digital machine adjustments the visitors circulate. After implementing Mobility Optimized Networking (MON), egress visitors from that digital machine doesn’t trombone again to on-premises. As an alternative, it bypasses the Community Extensions (NE) IPSEC tunnel. Visitors for that digital machine will now egress out of the Azure VMware Resolution NSX-T Tier-1 Gateway> NSX-T Tier-0 Gateway>Azure Digital WAN.

Enabling Mobility Optimized Networking (MON) for a selected prolonged community and a digital machine ends in a change. From Azure VMware Resolution NSX-T, it injects a /32 host route again to Azure Digital WAN. Azure Digital WAN advertises this /32 route again to on-premises, Digital Networks, and Department Networks (S2S VPN, P2S VPN, SDWAN). The aim of this /32 host route is to make sure that visitors from on-premises, Digital Networks, and Department Networks does not use the Community Extensions (NE) IPSEC tunnel when destined for the Mobility Optimized Networking (MON) enabled Digital Machine. Visitors from supply networks is directed straight to the Mobility Optimized Networking (MON) enabled Digital Machine as a result of /32 route that’s realized.

With ExpressRoute to ExpressRoute transitivity enabled on the Safe Hub and Routing-Intent enabled, the Safe Hub sends the default RFC 1918 addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to each the on-premises and Azure VMware Resolution. Along with the default RFC 1918 addresses, each on-premises and Azure VMware Resolution study extra particular routes from Azure Digital Networks and Department Networks (S2S VPN, P2S VPN, SDWAN) which might be related to the hub. Nonetheless, on-premises networks do not study any particular routes from the Azure VMware Resolution, nor does the reverse happen. As an alternative, each environments depend on the default RFC 1918 addresses to facilitate routing again to 1 one other by way of the Hub firewall. Because of this extra particular routes, corresponding to HCX Mobility Optimized Networking (MON) Host Routes, aren’t marketed from the Azure VMware Resolution ExpressRoute to the on-premises-based ExpressRoute circuit and vice-versa. The lack to study particular routes introduces uneven visitors flows. Visitors egresses Azure VMware Resolution by way of the NSX-T Tier-0 gateway, however returning visitors from on-premises returns over the Community Extensions (NE) IPSEC tunnel.

To right any visitors asymmetry, it’s worthwhile to modify the HCX Mobility Optimized Networking (MON) Coverage Routes. Mobility Optimized Networking (MON) coverage routes decide which visitors goes again to the on-premises Gateway by way of an L2 extension. Additionally they determine which visitors is routed by means of the Azure VMware Resolution NSX Tier-0 Gateway.

If a vacation spot IP matches and is ready to “permit” within the Mobility Optimized Networking (MON) coverage configuration, then two actions happen. First, the packet is recognized. Second, it is despatched to the on-premises gateway by means of the HCX Community Extension equipment.

If a vacation spot IP does not match, or is ready to “deny” within the Mobility Optimized Networking (MON) coverage, the system sends the packet to the Azure VMware Resolution Tier-0 for routing.

HCX Coverage Routes