Contents
1.SSL Certificate Acquisition ( Let's Encrypt )
Install the latest open ssl
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# dnf install openssl-devel |
1.1 Certificate Installation
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# dnf -y install certbot # certbot certonly --webroot -w /var/www/html/[FQDN] -d [FQDN] |
Registration of e-mail address and agreement to terms of use are required for the first time only.
Specify an email address to receive
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Saving debug log to /var/log/letsencrypt/letsencrypt.log Enter email address (used for urgent renewal and security notices) (Enter 'c' to cancel): <mail address> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Please read the Terms of Service at https://letsencrypt.org/documents/LE-SA-v1.3-September-21-2022.pdf. You must agree in order to register with the ACME server. Do you agree? - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (Y)es/(N)o: y - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Would you be willing, once your first certificate is successfully issued, to share your email address with the Electronic Frontier Foundation, a founding partner of the Let's Encrypt project and the non-profit organization that develops Certbot? We'd like to send you email about our work encrypting the web, EFF news, campaigns, and ways to support digital freedom. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (Y)es/(N)o: y Account registered. Requesting a certificate for <FQDN> Successfully received certificate. Certificate is saved at: /etc/letsencrypt/live/<FQDN>/fullchain.pem Key is saved at: /etc/letsencrypt/live/<FQDN>/privkey.pem This certificate expires on 2023-11-16. These files will be updated when the certificate renews. Certbot has set up a scheduled task to automatically renew this certificate in the background. We were unable to subscribe you the EFF mailing list because your e-mail address appears to be invalid. You can try again later by visiting https://act.eff.org. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - If you like Certbot, please consider supporting our work by: * Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate * Donating to EFF: https://eff.org/donate-le - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - |
"Successfully received certificate.Success if displayed
The following certificate is obtained under [/etc/letsencrypt/live/<FQDN>] as described in the message
cert.pem ⇒ SSL server certificate (including public key)
chain.pem ⇒ intermediate certificate
fullchain.pem ⇒ File containing cert.pem and chain.pem combined
privkey.pem ⇒ private key
※ Obtaining a Let's Encrypt certificate when the web server is not running
It is a prerequisite that the server on which the work is to be performed is accessible from the Internet at port 80.
Use the simple Web server function by specifying [--standalone].
# -d [FQDN from which you want to obtain a certificate
# FQDN (Fully Qualified Domain Name) : Hostname. Domain name without abbreviation
# If there are multiple FQDNs for which you want to obtain certificates, specify multiple -d [FQDNs for which you want to obtain certificates]
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# certbot certonly --standalone -d <FQDN> |
Renewing certificates already obtained
# Renew all certificates with an expiration date of less than 30 days
# If you want to renew regardless of the number of days remaining on the expiration date, specify [--force-renewal] as well
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# certbot [--force-renewal] renew |
1.2 Automatic renewal of certificates (Let's Encrypt)
①Pre-registration testing
First, test the automatic update using the following --dry-run option.
With this option, certificates are not renewed, only checked, so there is no need to worry about getting caught in the limit on the number of times a certificate can be obtained.
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# certbot renew --dry-run |
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Saving debug log to /var/log/letsencrypt/letsencrypt.log - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Processing /etc/letsencrypt/renewal/<FQDN> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Account registered. Simulating renewal of an existing certificate for <FQDN> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Congratulations, all simulated renewals succeeded: /etc/letsencrypt/live/<FQDN>/fullchain.pem (success) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - |
②Using Systemd Timer
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# systemctl cat certbot-renew.timer # /usr/lib/systemd/system/certbot-renew.timer [Unit] Description=This is the timer to set the schedule for automated renewals [Timer] OnCalendar=*-*-* 00/12:00:00 RandomizedDelaySec=12hours Persistent=true [Install] WantedBy=timers.target |
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# systemctl enable --now certbot-renew.timer |
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# systemctl list-timers certbot-renew.timer NEXT LEFT LAST PASSED UNIT ACTIVATES Sat 2023-08-19 14:48:53 JST 5h 52min left n/a n/a certbot-renew.timer certbot-renew.service 1 timers listed. Pass --all to see loaded but inactive timers, too. |
2. Converting Apache to https
Install the following
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# dnf -y install mod_ssl |
2.1 Edit ssl.conf file
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# vi /etc/httpd/conf.d/ssl.conf Line 43 Uncomment and change DocumentRoot "/var/www/html/<FQDN>" Line 44 Uncomment and change ServerName <FQDN>:443 Line 85 Make it a comment and add it below # SSLCertificateFile /etc/pki/tls/certs/localhost.crt SSLCertificateFile /etc/letsencrypt/live/<FQDN>/cert.pem Line 93 Make it a comment and add it below # SSLCertificateKeyFile /etc/pki/tls/private/localhost.key SSLCertificateKeyFile /etc/letsencrypt/live/<FQDN>/privkey.pem Line 103 add SSLCertificateChainFile /etc/letsencrypt/live/<FQDN>/chain.pem |
Restart Apache.
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# systemctl restart httpd |
Allow https in Firewall
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# firewall-cmd --add-service=https --permanent success # firewall-cmd --reload success |
2.2 Redirect HTTP to HTTPS
Create .htaccess under /var/www/html/<FQDN>/.
Contents of .htaccess
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RewriteEngine On RewriteCond %{HTTPS} off RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L] |
3. SSL/TLS (Let's Encrypt) settings on the mail server
3.1 Obtaining a certificate for the mail server
Obtain a certificate for the mail server, but it cannot be obtained in the same way as above, so the following with the "--standalone" option fails.
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# certbot certonly --standalone -d mail.<domain name> |
If I stop the web server and then do it, it succeeds as follows
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# systemctl stop httpd.service # certbot certonly --standalone -d mail.<domain name> |
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Saving debug log to /var/log/letsencrypt/letsencrypt.log Requesting a certificate for mail.<domain name> Successfully received certificate. Certificate is saved at: /etc/letsencrypt/live/mail.<domain name>/fullchain.pem Key is saved at: /etc/letsencrypt/live/mail.<domain name>/privkey.pem This certificate expires on 2023-11-16. These files will be updated when the certificate renews. Certbot has set up a scheduled task to automatically renew this certificate in the background. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - If you like Certbot, please consider supporting our work by: * Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate * Donating to EFF: https://eff.org/donate-le - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - |
3.2 Postfix Configuration
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# vi /etc/postfix/main.cf Per Line 709,715: comment out #smtpd_tls_cert_file = /etc/pki/tls/certs/postfix.pem #smtpd_tls_key_file = /etc/pki/tls/private/postfix.key Add to the last line smtpd_use_tls = yes smtp_tls_mandatory_protocols = !SSLv2, !SSLv3 smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3 smtpd_tls_cert_file = /etc/letsencrypt/live/mail.<domain name>/fullchain.pem smtpd_tls_key_file = /etc/letsencrypt/live/mail.<domain name>/privkey.pem smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache |
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# vi /etc/postfix/master.cf Line 17-20 : Uncomment submission inet n - n - - smtpd -o syslog_name=postfix/submission -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes Line 29-32 : Uncomment smtps inet n - n - - smtpd -o syslog_name=postfix/smtps -o smtpd_tls_wrappermode=yes -o smtpd_sasl_auth_enable=yes |
3.3 Dovecot Settings
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# vi /etc/dovecot/conf.d/10-ssl.conf Line 8：confirmation ssl = yes Line 14,15：Comment and add certificate/key file designation below #ssl_cert = </etc/pki/dovecot/certs/dovecot.pem #ssl_key = </etc/pki/dovecot/private/dovecot.pem ssl_cert = </etc/letsencrypt/live/mail.<domain name>/fullchain.pem ssl_key = </etc/letsencrypt/live/mail.<domain name>/privkey.pem |
Allow Port 587 in firewall
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# firewall-cmd --add-port=587/tcp --permanent # firewall-cmd --reload # systemctl restart postfix dovecot |
3.4 Thunderbird Settings
Receiving server
Port : 143
Connection security : STARTTLS
Authentication method : Normal password
Sending server
Port : 587
Connection security : STARTTLS
Authentication method : Normal password
