We are using Windows 2008 R2 and IIS7. It is a VMWare VM instance.

Recently I added a new IP to NIC. Then using the IIS manager UI to add a new IIS entry binding to ip A and port 80. The NIC have existing IP B and C.

However it never return a web site when browse http://A/. I tried telnet IP A 80 and no respond. I have tried change to port 443 and https://A/. There is no different.

So I tested it by change the IIS entry to ip B:443. It is working. Telnet test passed too.

Then I tested ti by change the same IIS entry to ip C:8888 (to make sure no other application is listening to the port by mistake). It is working. Telnet test passed.

So the only problem is the new IP cannot be used in my IIS7! From the IIS manager UI I cannot find any entry is listening to IP A beside the problematic entry. I search in applicationhost.config and have same result. How can I troubleshoot it?

P.S. IP A is pingable. When I remove IP A from network card it will immediately become non-pingable.

  • 1
    sounds like another application is hogging port 80.check with netstat -an | findstr 80
    – rob
    Apr 12 '16 at 6:20
  • netstat find nothing for the problematic IP
    – Mark
    Apr 12 '16 at 7:54

Sorry, I just find the answer. It is a bug of IIS7 (Microsoft said it is by design). Reference: IIS binds to all IP addresses on a server when you install IIS 7.0 on Windows Server 2008

First, I run netsh http show iplisten to check which IP is listening in http service. Only the old IPs B, C and is listed.

So I run netsh http add iplisten xxx.xxx.x.x (IP A) to add to listening list.

Finally reboot the server (the article suggest restart http which I don't suggest. It is because some dependency of http maybe missing. If you restart http it may cause another problem.) In fact, I don't need to reboot to make the new IP (A) work and listen. But I just reboot it for safe.

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