IIS response headers vary depending on the network route

Question

Hi,

I used IIS to hide the Server version. The version is 10.

However, when checking the raw data of the response headers, the Server field disappears correctly in some cases, but in others it does not.

It does not disappear when accessing internally via VPN, but disappears when not accessing via VPN.

Also, in the case of connection from the Internet from home, there are both environments where the connection disappears and cases where it does not disappear.

In short, response headers differ depending on the route that refers to IIS.

I did a lot of searching about this case, but couldn't find any cases like this.

Does anyone know the reason for this?

The method of check is the "curl" command.

(I also checked on Chrome, but it was the same)

I thought it was driven by cash, but this situation has been going on for about a week, so I'm wondering about that as well.

Thanks.

Answer 1

The most obvious cause is that the requests are being routed to different servers/sites. One for internet requests and one for private network requests.

Do an NSlookup in each case to get the IP for the site name and then try to track down where that goes.

When you test, use a unique page name or query string to identify where the test is coming from.

Https://www.mysite.com/testfromhomeovervpn.htm or Https://www.mysite.com/testovertheinternet.htm

Make note of which url returns the header. Then check the IIS log for the site and verify that you see all of your tests in the log. If you don't, then the request is going somewhere else.

Answer 2

Hi MotoX80,

Thank you for your response.

I did NSlookup. But the IP adresses are same... from private network / internet.

Can you think of any other causes?

Thanks.