Reverse Proxy to HTTP server via IIS with SSL

Question

web.config

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <rewrite>
            <rules>
                <rule name="ReverseProxyApi" stopProcessing="true">
                    <match url="api/(.*)" />
                    <action type="Rewrite" url="http://localhost:3000/{R:1}" />
                </rule>
                <rule name="ReverseProxyClient" enabled="true" stopProcessing="true">
                    <match url="(.*)" />
                    <conditions>
                        <add input="{CACHE_URL}" pattern="^(.+)://" />
                    </conditions>
                    <action type="Rewrite" url="{C:1}://localhost:3001/{R:1}" />
                    <serverVariables>
                        <set name="HTTP_SEC_WEBSOCKET_EXTENSIONS" value="" />
                    </serverVariables>
                </rule>
            </rules>
        </rewrite>
    </system.webServer>
</configuration>

I have successfully created a reverse proxy from http://localhost:9999 to my http://localhost:3000 (NestJS api server) and http://localhost:3001 (NextJS client server) using the above config in rewrite url.

My problem is that I am geting an error when I tried to bind https://localhost:8888 to the same site. I made sure that the https url is in the site bindings. I also have a self signed ssl certificate with it.

This is the error I am getting:

As you can see here https://localhost:8888 is in the site bindings

This is self signed certificate that I am using

I have no idea what is wrong in my setup. I have tried to restart both the website and the whole IIS server but I am getting the same error.

Answer 1

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <rewrite>
            <rules>
                <rule name="ReverseProxyApi" stopProcessing="true">
                    <match url="api/(.*)" />
                    <action type="Rewrite" url="http://localhost:3000/{R:1}" />
                </rule>
                <rule name="ReverseProxyClient" enabled="true" stopProcessing="true">
                    <match url="(.*)" />
                    <conditions>
                        <add input="{CACHE_URL}" pattern="^(.+)://" />
                    </conditions>
                    <action type="Rewrite" url="{MapProtocol:{C:1}}://localhost:3001/{R:1}" />
                    <serverVariables>
                        <set name="HTTP_SEC_WEBSOCKET_EXTENSIONS" value="" />
                    </serverVariables>
                </rule>
            </rules>
            <rewriteMaps>
                <rewriteMap name="MapProtocol">
                    <add key="https" value="http" />
                    <add key="wss" value="ws" />
                </rewriteMap>
            </rewriteMaps>
        </rewrite>
    </system.webServer>
</configuration>

This web config works. I think what was wrong in my previous config is that https://localhost:8888 is redirected to https://localhost:3001 which does not exist (because of the {C:1}).

With this new config:
ws:// or wss:// -> ws://
http:// or https:// -> http://