Route Client VPN traffic over public IP on vMX

[PKT1099]

We access a vendor website that is locked down with an IP whitelist.

Our workforce is primarily remote (work from home). We want to be able to only have to whitelist one IP address across all our remote users.

We have a vMX in Azure which our employees use to access Azure resources via AnyConnect Client VPN. The vMX is configured in Passthrough / VPN Concentrator mode. I'm using split tunneling and dynamic client routing in the client VPN settings to specify that traffic to this website should go over the VPN. My goal was to have all traffic appear to be coming from the public IP of the vMX so we could whitelist that IP address.

For some reason this is not working.

• When users try to connect to the vendor website from an IP address that is not whitelisted, the site displays a "Website Restricted" message.

• When our users are connected to the vMX using AnyConnect, they do not get the "Website Restricted" message, but the page doesn't load. It eventually times out after a long period.

• So there is a different behavior when connected to the VPN vs not connected.

We have another vendor who does something similar with their website. This vendor has a non-Meraki site-to-site VPN connection to our vMX. They have whitelisted the public IP of our vMX, and the split tunneling works as expected. The only difference between the two vendors is that we have a site-to-site VPN tunnel with the second vendor, the one for whom the website connection works.

Has anyone else been able to get something like this working? I'd appreciate any ideas or suggestions.

[MartinLL]

Dont use the vMX instance public ip. In fact i'm pretty sure that you cant.

The vMX VM public IP is not something the vMX can NAT to, so you wont reach the internet that way.

What i would do instead is to pin all traffic egressing the vMX towards Azure to an Azure Firewall or something. This way you can create DNAT/SNAT rules on the Azure Firewall, have your vendors whitelist the AZFW Public IP and reach it that way instead.

look at my post history. I have explained this setup a few times.

if you have more questions after reading my posts feel free to ask.

[PKT1099]

I have a single vnet in Azure with multiple subnets. I also have a NAT Gateway.

The NAT Gateway is associated with the subnet containing my hosted servers. This causes traffic coming from those servers to appears to be originating from a single IP address. I had the vendor (who hosts the website) whitelist the public IP address of the NAT Gateway, and I can access the website from those servers.

Is there any way to do this for traffic coming from the AnyConnect subnet? 

I've tried associating the NAT Gateway with the AnyConnect subnet, but I am still unable to access the website.

I'm really trying to avoid having to spin up and pay for a second firewall (whether it be Meraki or Azure).