Reverse proxy

It is recommended to place both the FoxIDs Azure App service and the FoxIDs Control Azure App service behind a reverse proxy.

The custom primary domains is exposed through the reverse proxy alongside optionally custom domains.

The FoxIDs service support custom domains which is handled with domain rewrite through the reverse proxy.

FoxIDs support custom domains if it is behind a reverse proxy and the access is restricted by the X-FoxIDs-Secret HTTP header or the Settings:TrustProxyHeaders setting is set to true in the FoxIDs App Service configuration.
If not behind a reverse proxy FoxIDs support custom domains by reading the HTTP request domain and using the domain as a custom domain if the Setting:RequestDomainAsCustomDomain setting is set to true.

Restrict access

Both the FoxIDs service and FoxIDs Control sites can restrict access based on the X-FoxIDs-Secret HTTP header.
The access restriction is activated by adding a secret with the name Settings--ProxySecret in Key Vault.

  1. Grant your IP address access through the Key Vault firewall Configure reverse proxy secret - firewall

  2. Grant your user List and Set permissions in Access policies. Configure reverse proxy secret - permissions

  3. Add the Settings--ProxySecret secret Configure reverse proxy secret

  4. After successfully configuration, remove you IP address and permissions.

The sites needs to be restarted to read the secret.

After the reverse proxy secret has been configured in Key Vault the reverse proxy needs to add the X-FoxIDs-Secret HTTP header in all backed calls to FoxIDs to get access.

Read HTTP headers

FoxIDs service support reading the client IP address in the following prioritized HTTP headers:

  1. CF-Connecting-IP
  2. X-Azure-ClientIP
  3. X-Forwarded-For

FoxIDs service support reading the custom domain (host name) exposed on the revers proxy in the following prioritized HTTP headers:

  2. X-Forwarded-Host

The host header is only read if access is restricted by the X-FoxIDs-Secret HTTP header.

Supported and tested reverse proxies

FoxIDs generally support all reverse proxies. The following reverse proxies is tested to work with FoxIDs.

Azure Front Door

Azure Front Door can be configured as a reverse proxy. Azure Front Door rewrite domains by default.

Do NOT enable caching. The Accept-Language header is not forwarded if caching is enabled. The header is required by FoxIDs to support cultures.


  • Add a Azure Front Door endpoint for both the FoxIDs App Service and the FoxIDs Control App Service
  • In the Networking section of the App Services. Enable access restriction to only allow traffic from Azure Front Door
  • Optionally add a Front Door endpoint for both the FoxIDs App Service and the FoxIDs Control App Service test slots
  • Restrict access to the App Services test slots
  • Add the Settings:TrustProxyHeaders setting with the value true and select Deployment slot setting in the FoxIDs App Service configuration to support custom domains (optionally also add the setting in the test slot)
  • Disable Session affinity
  • Optionally configure WAF policies


Cloudflare can be configured as a reverse proxy. But Cloudflare require a Enterprise plan to rewrite domains (host headers). The X-FoxIDs-Secret HTTP header should be added.


Internet Information Services (IIS) Application Request Routing (ARR) Proxy require a Windows server. ARR Proxy rewrite domains with a rewrite rule. The X-FoxIDs-Secret HTTP header can optionally be added (recommended depended on the infrastructure) but is required to support custom domain.

An accept all external exposed domains rule can be configured. This example is a global rule, rules can also be added to websites.
Optionally both requiring (secret1) and sending (secret2) in a X-FoxIDs-Secret HTTP header. You could require a X-FoxIDs-Secret HTTP header if you have a reverse proxy in front of the ARR Proxy.

    <rule name="my-rule-name" patternSyntax="Wildcard" stopProcessing="true">
        <match url="*" />
            <add input="{HTTP_X-FoxIDs-Secret}" pattern="... secret1 ..." ignoreCase="false" />
        <action type="Rewrite" url="{R:1}" />
            <set name="HTTP_X-ORIGINAL-HOST" value="{HTTP_HOST}" />
            <set name="HTTP_X-FoxIDs-Secret" value="... secret2 ..." />