Following on from my earlier blog, I had managed to successfully publish the CRL to my web server. However, in order to verify everything is working, you should browse to the URL and access the .CRL files.
I could browse to the files, either with or without HTTPS:
…but I could not download them; I received a 404 error message. I did some digging and verified that I had set allowDoubleEscaping, and that the .CRL was specificed as a valid MIME type on the web server. I checked the IIS logs and they indicated this was a MIME type error. So what was wrong?
Well the clue is in the above screenshot! Both files are missing their .CRL extension. Verifying the MIME entries made me realise that the published CRL files were missing their .crl extension. Hence IIS did not have a valid MIME type to handle the files which resulted in the 404 error.
I manually added .CRL to one of the files and bingo, I could download the content. I then went back to the CA to review the previous work I had done, setting up the Certificate Distribution Point.
I found a glaring oversight:
I had missed the .CRL extension when creating the file location. I removed and added a new location, this time including the .CRL extension and I could now download the file via the website:
The final job is to confirm the new certificates contain the CDP. All done here!