With advent of Letsencrypt service this may seem unnecessary. But sometimes you just need to quickly generate SSL certificate to secure internal/test service…
Install OpenSSL, Debian/Ubuntu
sudo apt-get -y install openssl
or Centos
yum install openssl
Create file
vim multidomains.conf
# openssl req -sha256 -config multidomains.conf -keyout server.key -out server.csr -new [ req ] default_bits = 4096 # avoid to specify a value under 1024... prompt = no # if you want to type a lot of stuff, say Yes here encrypt_key = no # see question in our FAQ to help you... default_md = sha256 distinguished_name = dn [ dn ] C = PL O = Cebula Computer Systems 0.CN = hostA.mielnet.pl 1.CN = aka.mielnet.pl L = Kocborowo OU = IT Services
Generate key and csr with
openssl req -sha256 -config multidomains.conf -keyout server.key -out server.csr -new # you can display CSR with: openssl req -text -noout -in server.csr # pay attention to Signature Algorithm, we want sha256WithRSAEncryption
Finally generate certificate
openssl x509 -sha256 -days 3650 -req -in server.csr -signkey server.key > server.crt # you can display certificate with: openssl x509 -text -in server.crt # again, we want Signature Algorithm sha256WithRSAEncryption