Contents
1. .Obtain an SSL certificate ( Let's Encrypt )
Install the latest open ssl
|
1 |
# dnf install openssl-devel |
1.1 advance preparation
1.Package management system Snappy installed
Since the SSL certificate issuing tool "certbot" of Let's Encrypt is recommended to be installed using "snap" after 2021, install Snapd first.(Can also be installed the traditional way with dnf or yum)
|
1 2 3 |
# dnf install epel-release # dnf upgrade # dnf install snapd |
Enable systemd unit to manage the main snap communication socket
|
1 2 |
# systemctl enable --now snapd.socket Created symlink /etc/systemd/system/sockets.target.wants/snapd.socket → /usr/lib/systemd/system/snapd.socket. |
Enable Classics Snap support
|
1 |
# ln -s /var/lib/snapd/snap /snap |
Bring snapd version up to date
|
1 |
# snap install core |
If the above fails, run the following command instead (the core package will be installed along with the package called hello-world)
|
1 |
# snap install hello-world |
Update core package
|
1 |
# snap refresh core |
Version Check
|
1 2 3 4 5 6 |
# snap --version snap 2.58.3-1.el9 snapd 2.58.3-1.el9 series 16 almalinux 9.2 kernel 5.14.0-284.11.1.el9_2.x86_64 |
Log out and log in again or reboot the system to ensure that the snap path is updated correctly
2..certbot package install
|
1 2 |
# snap install --classic certbot certbot 2.6.0 from Certbot Project (certbot-eff?) installed |
Create symbolic link to /snap/bin/certbot
|
1 |
# ln -s /snap/bin/certbot /usr/bin/certbot |
Confirmation
|
1 2 3 4 5 |
# ls -la /usr/bin/certbot lrwxrwxrwx 1 root root 17 May 19 14:17 /usr/bin/certbot -> /snap/bin/certbot # ls -la /snap/bin/certbot lrwxrwxrwx 1 root root 13 May 19 14:16 /snap/bin/certbot -> /usr/bin/snap |
1.2 Obtaining Certificates
|
1 |
# 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
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 |
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 2023-08-17. 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - |
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 stuck with a limit on the number of times a certificate can be obtained.
|
1 |
# certbot renew --dry-run |
②When you install the snap version of certbot, the automatic certificate renewal function is also installed.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 |
# systemctl list-timers | less NEXT LEFT LAST PASSED UNIT ACTIVATES Sat 2023-05-20 09:40:00 JST 8min left Sat 2023-05-20 09:30:00 JST 1min 13s ago sysstat-collect.timer sysstat-collect.service Sat 2023-05-20 09:42:49 JST 11min left - - systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service Sat 2023-05-20 09:55:00 JST 23min left Sat 2023-05-20 09:28:49 JST 2min 24s ago pmlogger_check.timer pmlogger_check.service Sat 2023-05-20 09:55:10 JST 23min left Sat 2023-05-20 09:28:49 JST 2min 24s ago pmlogger_farm_check.timer pmlogger_farm_check.service Sat 2023-05-20 09:58:00 JST 26min left Sat 2023-05-20 09:28:49 JST 2min 24s ago pmie_check.timer pmie_check.service Sat 2023-05-20 09:58:10 JST 26min left Sat 2023-05-20 09:28:49 JST 2min 24s ago pmie_farm_check.timer pmie_farm_check.service Sat 2023-05-20 10:29:42 JST 58min left - - dnf-makecache.timer dnf-makecache.service Sat 2023-05-20 17:41:00 JST 8h left - - snap.certbot.renew.timer snap.certbot.renew.service Sun 2023-05-21 00:00:00 JST 14h left Sat 2023-05-20 09:28:10 JST 3min 3s ago logrotate.timer logrotate.service Sun 2023-05-21 00:00:00 JST 14h left Sat 2023-05-20 09:28:10 JST 3min 3s ago mlocate-updatedb.timer mlocate-updatedb.service Sun 2023-05-21 00:00:00 JST 14h left - - sa-update.time: |
snap.certbot.renew.timer is registered
Check the unit file snap.certbot.renew.timer
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
# vi /etc/systemd/system/snap.certbot.renew.timer [Unit] # Auto-generated, DO NOT EDIT Description=Timer renew for snap application certbot.renew Requires=var-lib-snapd-snap-certbot-2414.mount After=var-lib-snapd-snap-certbot-2414.mount X-Snappy=yes [Timer] Unit=snap.certbot.renew.service OnCalendar=*-*-* 04:49 OnCalendar=*-*-* 15:16 [Install] WantedBy=timers.target |
According to the above configuration, it will attempt to update at 4:49 and 15:16 every day as specified in the OnCalender parameter(However, the set time changes randomly with each update)
Check the unit file snap.certbot.renew.service
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
# vi /etc/systemd/system/snap.certbot.renew.service [Unit] # Auto-generated, DO NOT EDIT Description=Service for snap application certbot.renew Requires=var-lib-snapd-snap-certbot-2414.mount Wants=network.target After=var-lib-snapd-snap-certbot-2414.mount network.target snapd.apparmor.service X-Snappy=yes [Service] EnvironmentFile=-/etc/environment ExecStart=/usr/bin/snap run --timer="00:00~24:00/2" certbot.renew SyslogIdentifier=certbot.renew Restart=no WorkingDirectory=/var/snap/certbot/2414 TimeoutStopSec=30 Type=oneshot |
However, the web server using the certificate will not be restarted, so set up a script to run automatically after the update
|
1 2 3 4 |
# vi /etc/letsencrypt/renewal-hooks/post/web_restart.sh #!/bin/bash systemctl reload httpd |
|
1 |
# chmod 755 /etc/letsencrypt/renewal-hooks/post/web_restart.sh |
2. Converting Apache to https
Install the following just in case
|
1 |
# dnf -y install mod_ssl |
2.1 Edit ssl.conf file
|
1 2 3 4 5 6 7 8 9 10 11 12 13 |
# vi /etc/httpd/conf.d/ssl.conf ●Line 43 : Uncomment and change DocumentRoot "/var/www/html/<FQDN>" ●Line 44 : Uncomment and change ServerName <Domain>: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.
|
1 |
# systemctl restart httpd |
Allow https in Firewall
|
1 2 3 4 |
# firewall-cmd --add-service=https --permanent success # firewall-cmd --reload success |
2.2 Redirect HTTP communications to HTTPS
Create .htaccess under /var/www/html/[FQDN]/.
Contents of .htaccess
|
1 2 3 |
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.
|
1 |
# certbot certonly --standalone -d mail.<domain name> |
If I stop the web server once and then do it, it succeeds as follows
|
1 2 |
# systemctl stop httpd.service # certbot certonly --standalone -d mail.<domain name> |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
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 2023-08-17. 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
|
1 2 3 4 5 6 7 8 9 10 11 |
# vi /etc/postfix/main.cf ●Per lines 709, 715 : comment #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 |
|
1 2 3 4 5 6 7 8 9 10 11 |
# vi /etc/postfix/master.cf ● Line 19-22 : Uncomment submission inet n - n - - smtpd -o syslog_name=postfix/submission -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes ● Line 31-34 : 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
|
1 2 3 4 5 6 |
# vi /etc/dovecot/conf.d/10-ssl.conf ● Line 8：confirmation ssl = yes ● Line 14,15：Make it a comment and add certificate/key file designation under it 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
|
1 2 |
# firewall-cmd --add-port=587/tcp --permanent # firewall-cmd --reload |
|
1 |
# systemctl restart postfix dovecot |
3.4 Thunderbird Settings
Receiving servers
Port : 143
Connection security : STARTTLS
Authentication method : Normal password
Sending server
Port : 587
Connection security : STARTTLS
Authentication method : Normal password
