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 Answer when utilizing Azure Safe Digital WAN with Routing Intent. You be taught 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 attitude of an Azure VMware Answer 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 help or with a safety requirement to examine visitors between Azure VMware Answer and on-premises on the hub firewall, a help ticket have to 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 just supported with Digital WAN Normal SKU. Safe Digital WAN with Routing Intent offers the aptitude to ship all Web visitors and Non-public community visitors (RFC 1918) to a safety answer like Azure Firewall, a third-party Community Digital Equipment (NVA), or SaaS answer. Within the situation, we now have a community topology that spans a single area. There’s one Digital WAN with a single hub situated within the Area. The Hub has its personal occasion of an Azure Firewall deployed, basically 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 only area additionally has an Azure VMware Answer Non-public Cloud and an Azure Digital Community. There’s additionally an on-premises web site 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 Answer, on-premises, Azure Digital Networks, and the Web.

This part focuses on solely the Azure VMware Answer non-public cloud. The Azure VMware Answer 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 Answer over connection “D”. Along with the default RFC 1918 addresses, Azure VMware Answer learns extra particular routes from Azure Digital Networks and Department Networks (S2S VPN, P2S VPN, SDWAN) which are linked to the hub. Azure VMware Answer would not be taught 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 discovered from connection “D”. This visitors transits via the Hub firewall, as proven within the diagram. The Hub firewall has the particular routes for on-premises networks and routes visitors towards the vacation spot over connection “E”. Visitors from Azure VMware Answer, heading in the direction of Digital Networks, will transit the Hub firewall. For extra data, see the visitors circulation part.

The diagram illustrates visitors flows from the attitude of the Azure VMware Answer Non-public Cloud.

Visitors Stream Chart

This part focuses solely on the on-premises web site. As proven within the diagram, the on-premises web site 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 are linked to the hub. On-premises would not be taught particular routes from Azure VMware Answer networks. For routing visitors again to Azure VMware Answer networks, it makes use of the default RFC 1918 addresses that it discovered from connection “E”. This visitors transits via the Hub firewall, as proven within the diagram. The Hub firewall has the particular routes for Azure VMware Answer 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 circulation 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, you need to promote extra particular routes again to Azure on your on-premises networks.

Observe
Should you’re at present promoting the default RFC 1918 addresses from on-premises to Azure and want to proceed this observe, it is advisable 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 attitude of on-premises.

Visitors Stream 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 sources within the Digital Community be taught 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 sources within the Digital Community do not be taught particular routes from outdoors of their Digital Community. With Routing Intent enabled, all sources within the Digital Community at present 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 circulation part for extra detailed data.

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

Visitors Stream Chart

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

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

Though you should use all three choices with Single Area Safe Digital WAN with Routing Intent, “Choice 1: Web Service hosted in Azure” is the most suitable choice when utilizing Safe Digital WAN with Routing Intent and is the choice that’s used to supply web connectivity within the situation. The rationale why “Choice 1” is taken into account the most suitable 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. Nevertheless, it’s also possible to promote a default route 0.0.0.0/0 for web connectivity to downstream sources. With Routing Intent, you possibly can select to generate a default route from the hub firewall. This default route is marketed to your Digital Community and to Azure VMware Answer. This part is damaged into two sections, one which explains web connectivity from an Azure VMware Answer 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 Answer from the Azure Digital WAN, you have to allow default route propagation in your Azure VMware Answer 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 necessary to notice that this setting should not be enabled for on-premises ExpressRoute circuits. As a finest observe, it is really helpful 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 mechanically marketed to the hub-peered Digital Community connections. You will 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 circulation part.

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

Visitors Stream Chart

HCX Mobility Optimized Networking (MON) is an non-obligatory function to allow when utilizing HCX Community Extensions (NE). Mobility Optimized Networking (MON) offers optimum visitors routing beneath sure situations to forestall community tromboning between the on-premises-based and cloud-based sources on prolonged networks.

Enabling Mobility Optimized Networking (MON) for a particular prolonged community and a digital machine adjustments the visitors circulation. 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 Answer NSX-T Tier-1 Gateway> NSX-T Tier-0 Gateway>Azure Digital WAN.

Enabling Mobility Optimized Networking (MON) for a particular prolonged community and a digital machine ends in a change. From Azure VMware Answer 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 would 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 because of the /32 route that’s discovered.

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 Answer. Along with the default RFC 1918 addresses, each on-premises and Azure VMware Answer be taught extra particular routes from Azure Digital Networks and Department Networks (S2S VPN, P2S VPN, SDWAN) which are linked to the hub. Nevertheless, on-premises networks do not be taught any particular routes from the Azure VMware Answer, 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, similar to HCX Mobility Optimized Networking (MON) Host Routes, aren’t marketed from the Azure VMware Answer ExpressRoute to the on-premises-based ExpressRoute circuit and vice-versa. The lack to be taught particular routes introduces uneven visitors flows. Visitors egresses Azure VMware Answer 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 is advisable 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 via the Azure VMware Answer NSX Tier-0 Gateway.

If a vacation spot IP matches and is about to “enable” 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 via the HCX Community Extension equipment.

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

HCX Coverage Routes