URL rewriting of subdirectory to diffent port using IIS - node.js

Question

I'm trying to integrate ASP.net and Node.js on a single server.
ASP.net is at localhost:8080
NodeJs is at localhost:4000
My expectation is here.
client ----> IIS Server ----> ASP.NET (no rewriting except /api/* localhost:80)
(rev.0970.co.kr) |---> Node.js (matching with /api/* localhost:4000)
Node app is executed as a windows service, and serve localhost:4000/api/ locally. And should be accessed with http://rev.0970.co.kr/api/signin
All request excepting /api/ should be served normal IIS asp.net. (ex. http://rev.0970.co.kr/index.aspx)
My Setting Steps
- install ARR and UrlRewrite module
- enable proxy of ARR
- add rule to urlrewrite section as below.
<rule name="Proxy">
<match url="api/(.*)"/>
<conditions>
<add input="{HTTP_HOST}" pattern="rev.0970.co.kr" />
</conditions>
<action type="Rewrite" url="http://localhost:4000/api/{R:1}" />
</rule>
Result
- http://rev.0970.co.kr/api/signin : success
- http://rev.0970.co.kr/index.aspx : fail - 404 not found
I thought http://rev.0970.co.kr/index.aspx did not match api/(.*), so IIS might render index.aspx.
When I removed whole rule settings of urlrewrite, http://rev.0970.co.kr/index.aspx worked.
What did I do wrong?
edit
Here is my full web.config file.
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<rewrite>
<outboundRules>
<rule name="ReverseProxyOutboundRule1" preCondition="ResponseIsHtml1">
<match filterByTags="A, Form, Img" pattern="^http(s)?://localhost:4000/(.*)" />
<action type="Rewrite" value="http{R:1}://rev.0970.co.kr/{R:2}" />
</rule>
<preConditions>
<preCondition name="ResponseIsHtml1">
<add input="{RESPONSE_CONTENT_TYPE}" pattern="^text/html" />
</preCondition>
</preConditions>
</outboundRules>
<rules>
<rule name="Proxy">
<match url="api/(.*)" />
<conditions>
<add input="{HTTP_HOST}" pattern="rev.0970.co.kr" />
</conditions>
<action type="Rewrite" url="http://localhost:4000/api/{R:1}" />
</rule>
</rules>
</rewrite>
<tracing>
<traceFailedRequests>
<add path="*">
<traceAreas>
<add provider="ASP" verbosity="Verbose" />
<add provider="ASPNET" areas="Infrastructure,Module,Page,AppServices" verbosity="Verbose" />
<add provider="ISAPI Extension" verbosity="Verbose" />
<add provider="WWW Server" areas="Security,CGI,RequestNotifications,Module,FastCGI" verbosity="General" />
</traceAreas>
<failureDefinitions timeTaken="00:00:00" statusCodes="404" />
</add>
</traceFailedRequests>
</tracing>
</system.webServer>
</configuration>