So I have been doing some OCSP performance bench-marking the last few weeks, one of the things we noticed while doing this is that OpenSSL does not set the HOST header when sending requests.
This is a problem when interacting with a OCSP responder that is on a shared host (a virtual host), without it the web-server doesn’t know which instance to send the request to. You can work around this by using the “-header” command, for example:
openssl ocsp -noverify -no_nonce -respout ocspglobalsignca.resp -reqout ocspglobalsignca.req -issuer globalsigng2.cer -cert globalsign.com.cer -url “http://ocsp2.globalsign.com/gsextendvalg2” -header “HOST'” “ocsp2.globalsign.com”
You need to ensure the HOST header is set consistently with the host contained in the -url switch but it works.