Generating Self Signed Certificate with Subject Alternate Names

March 24, 2020

Configuration file for running OpenSSL. You will need to specify the path to this in the below commands.

josh-desk.conf:

[req]

default_bits = 4096
prompt = no
default_md = sha256
x509_extensions = v3_req
distinguished_name = dn


[dn]
C = US
ST = MyState
L = MyCity
O = JoshDesktop
emailAddress = myemail.com
CN = cn


[v3_req]
subjectAltName = @alt_names

[alt_names]
DNS.1 = dev.com
DNS.2 = *.dev.com
DNS.3 = custom-dev.com
DNS.4 = *.custom-dev.com

Generate the .key and .crt files:

winpty openssl req -new -x509 -newkey rsa:4096 -sha256 -nodes -keyout josh-desk.key -days 3560 -out josh-desk.crt -config josh-desk.conf

Convert to .pfx:

winpty openssl pkcs12 -export -out josh-desk.pfx -inkey josh-desk.key -in josh-desk.crt

Then, REMEMBER to open the .pfx file and trust the certificate by putting it into the “Trusted Root Certification Authorities” store.