Dear Maintainer, I use openssl to check that certificate installed on different hosts match some DNS names. According "openssl s_client help" command, I use: openssl s_client -connect "debian.com:443" -verify_host debian.com But I get: *** damien@me:$ openssl s_client -connect "debian.com:443" -verify_host debian.com unknown option -verify_host usage: s_client args -host host - use -connect instead -port port - use -connect instead -connect host:port - who to connect to (default is localhost:4433) -verify_host host - check peer certificate matches "host" .... **** We can see that "verify_host" is unknown but present in the "usage". I found an openssl mail here : https://mta.openssl.org/pipermail/openssl- dev/2015-April.txt We can see that the option checked in the code is "-verify_hostname" and not "-verify_host" And yes, if I try: openssl s_client -connect "debian.com:443" -verify_hostname debian.com ->It works. It would be cool if you could path openssl to have the good display of the "usage". Regards