สร้าง SSL Cert

• เป็นขั้นตอนการสร้าง SSL key เตรียมไว้ใช้งานกับ postfix และ dovecot

1. สร้าง private key

# cd /etc/pki/tls/certs
# /usr/bin/openssl genrsa -aes128 2048 > eai.key

ตัวอย่าง

Generating RSA private key, 2048 bit long modulus
...
...
e is 65537 (0x10001)
Enter pass phrase: #set passphrase
Verifying - Enter pass phrase:  #confirm

2. ถอด Passphase ออกจาก private key ที่สร้างขึ้น

# /usr/bin/openssl rsa -in eai.key -out eai.key

ตัวอย่าง

Enter pass phrase for eai.key:  #input passphrase
writing RSA key

3. สร้าง csr

# /usr/bin/openssl req -utf8 -new -key eai.key -out eai.csr

ตัวอย่าง

You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:TH		#country
State or Province Name (full name) []:Bangkok		   #state
Locality Name (eg, city) [Default City]:Dusit		#city
Organization Name (eg, company) [Default Company Ltd]:EAI  	#company
Organizational Unit Name (eg, section) []:IT  	 #department
Common Name (eg, your name or your server's hostname) []:mail.eai.in.th  	 #server's FQDN
Email Address []:xxx@eai.in.th		#email address
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:		#Enter
An optional company name []:		#Enter

4. ทำการ generate key

# /usr/bin/openssl x509 -in eai.csr -out eai.crt -req -signkey eai.key -days 365

ตัวอย่าง

Signature ok
subject=/C=JP/ST=Hiroshima/L=Hiroshima/O=GTS/OU=Server World/CN=www.srv.world/emailAddress=xxx@eai.in.th
Getting Private key