Manually Generate a Certificate Signing Request (CSR) Using OpenSSL

how-to-create-csr-file

# CSR for single domain: abc.example.com 
openssl req -new -newkey rsa:2048 \
  -keyout abc.key \
  -nodes -out abc.csr  \
  -subj "/C=VN/ST=Ho Chi Minh/L=District 16/O=MyCompany/OU=MyTeam/CN=abc.example.com" 

# CSR for multi-domain - Subject Alternative Name (SAN): abc.example.com and xyz.example.com 
openssl req -new -newkey rsa:2048 \
  -keyout abcxyz.key \
  -nodes -out abcxyz.csr  \
  -subj "/C=VN/ST=Ho Chi Minh/L=District 16/O=MyCompany/OU=MyTeam/CN=abc.example.com" \
  -addext "subjectAltName = DNS:abc.example.com, DNS:xyz.example.com" 
  

# CSR for a Wildcard SSL Certificate: *.abc.example.com (including abc.example.com)
openssl req -new -newkey rsa:2048 \
  -keyout start.abc.key \
  -nodes -out star.abc.csr  \
  -subj "/C=VN/ST=Ho Chi Minh/L=District 16/O=MyCompany/OU=MyTeam/CN=*.abc.example.com" \
  -addext "subjectAltName = DNS:abc.example.com"