I am having the same issue described in this question: IIS 7 Still Serving old SSL Certificate

I have replaced an old SSL certificate with a new one and completely removed the old certificate from the server.

The poster above solved his issue when he realised that there was an ISA server between his web server and the Internet so he cleared the old certificate from the ISA cache and the problem was solved.

I have seen the same solution elsewhere: http://forums.iis.net/t/1182296.aspx

Unfortunately I am having trouble proving to my ISP that the issue is not on my server and that they are caching the old cert somewhere in their infrastructure.

I am 99.999% certain that the certificate installation and bindings are correct on IIS:

  • I have configured 2 bindings for the site with different alternate ports 9443 and 8443.
  • The old certificate was previously bound to the site on port 9443, both bindings now use the new certificate
  • I have configured the etc/hosts file to point the bound domain to so when I open a browser to the domain the requests are all local
  • If I visit the 2 URLs from another machine (i.e. via the Web) I get served the old cert on port 9443 and the new cert on port 8443
  • If I visit the 2 URLs from a browser on the web server I get served the new cert on both ports

I am 99.999% certain that the certificate is not cached on the client side:

  • I have hit the site from multiple browsers on both PC and mobile devices
  • I have hit the site over multiple connections, including my corporate LAN, home DSL and a mobile

My next step is to do something like a trace route of the TLS session establishment to figure out where the old certificate is being served from so I can prove to my ISP that this is something they need to solve.

Is this possible, what tools are available for this?

  • 1
    Try openssl s_client -connect server:port, then feed the certificate to openssl x509 -text -noout.
    – MadHatter
    Jul 10 '14 at 10:38
  • For external clients: does the hostname resolve to actual ip-address of your IIS server or something else.
    – HBruijn
    Jul 10 '14 at 10:38
  • @MadHatter: This just gives be a pretty view of the certificate I am being served. It just proves that it's the wrong one :). Is there a way to trace that connect session verbosely to see the IP of the machine that served the cert? Jul 10 '14 at 10:56
  • @HBruijn DNS is al working. The host name resolves correctly. Note that the same host with different ports has different behaviour. Jul 10 '14 at 10:57
  • 1
    @AdrianHope-Bailie I do not think that your ISP is caching anything in that regards, TBH. They usually do not do this... especially SSL traffic, and escpecially-especially on non-standard ports....! Also, how would they? They don't HAVE your certificate's private key, so it's not even possible...
    – MichelZ
    Jul 10 '14 at 11:53

I do not think that your ISP is caching anything in this regards, here are the reasons:

  • To serve YOUR certificate with YOUR thumbprint, they need to have access to YOUR private key
  • ISP's usually do not cache SSL traffic
  • ISP's escpecially do not cache SSL traffic on non-standard ports

So this seems to be an issue with your own server. Try rebooting it, try tracerouting it, try the suggestions from the comments like @MadHatter's: echo ""|openssl s_client -connect |openssl x509 -text -noout|&grep depth=0

Also, if you use SNI or stuff like that, make sure that the Default non-SNI Website in IIS has the correct certificate bound, as this is served to at least non-SNI clients, and I have seen problems when they did not match where there shouldn't have been problems.

  • I agree, check on the server itself to start with. And note that s_client does not semd SNI by default, only if you specify -servername whatever. But from where I am (Verizon US) nedbank.gyrusonline.com resolves via afrihost-win-1.*.stanchionpayments.com to, and :9443 gives me the .stanchionpayments.com cert without or with SNI. One warning: *on windows depending on your build, echo ""|openssl s_client may require you to hit a key even though input appears redirected. Jul 10 '14 at 12:19
  • The issue was with Windows' clever HTTP kernel thingy. This answer helped me solve it. stackoverflow.com/questions/12866117/… My server had two bindings on port 9443, one for and one for Jul 10 '14 at 12:23
  • >netsh http show sslcert Shows two bindings on port 9443, one for and one for with different certs. I don't know how those get in there or why the latter was not removed after the config in IIS was changed and IIS restarted. >netsh http delete sslcert ipport= Removed the binding for the old cert. My error in debugging was mapping the domain to in the etc/hosts file so local requests used the binding while external requests used the other. Jul 10 '14 at 12:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.