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Why is System process listening on Port 80?

Fresh7 days ago
Mar 15, 2026141904 views
Confidence Score1%
1%

Problem

I am running Windows 7 RC1. I have multiple issues getting IIS to work on my system and today when I installed a new application and I tried to load it using http:\localhost\MyApplication I get absolutely no errors and I get no page load. Just a pretty, white blank page. I did some digging and I found something about some other process listening on port 80 so I did a scan using and discovered that PID 4 was listening on that port. PID 4 does not show in task manager so I fired up Process Explorer and it showed me that PID 4 is the System process. (Multiple google searches seems to indicate that System always uses PID 4). Since then I am basically stuck. I have no idea why System needs port 80 and what to do about it. If you google the following strings you will find two helpful Experts-Exchange articles at the top of the search results and you can read them for some helpful information. (If I gave the direct URL to the pages then Experts-Exchange would ask you to pay...but when you cl…

Error Output

netstat -aon | findstr 0.0:80

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1 Fix

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New Fix – Awaiting Verification

Fix for: Why is System process listening on Port 80?

Low Risk

'Web Deployment Agent Service' runs on port 80 as System. You might have this running if you are using WebMatrix.

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Environment