How To Install opensmtpd on CentOS 8
Introduction
In this tutorial we learn how to install opensmtpd on CentOS 8.
What is opensmtpd
OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with some additional standard extensions. It allows ordinary machines to exchange e-mails with other systems speaking the SMTP protocol. Started out of dissatisfaction with other implementations, OpenSMTPD nowadays is a fairly complete SMTP implementation. OpenSMTPD is primarily developed by Gilles Chehade, Eric Faurot and Charles Longeau; with contributions from various OpenBSD hackers. OpenSMTPD is part of the OpenBSD Project. The software is freely usable and re-usable by everyone under an ISC license. This package uses standard “alternatives” mechanism, you may call “/usr/sbin/alternatives –set mta /usr/sbin/sendmail.opensmtpd” if you want to switch to OpenSMTPD MTA immediately after install, and “/usr/sbin/alternatives –set mta /usr/sbin/sendmail.sendmail” to revert back to Sendmail as a default mail daemon.
We can use yum or dnf to install opensmtpd on CentOS 8. In this tutorial we discuss both methods but you only need to choose one of method to install opensmtpd.
Install opensmtpd on CentOS 8 Using dnf
Update yum database with dnf using the following command.
sudo dnf makecache --refresh
The output should look something like this:
CentOS Linux 8 - AppStream 43 kB/s | 4.3 kB 00:00
CentOS Linux 8 - BaseOS 65 kB/s | 3.9 kB 00:00
CentOS Linux 8 - ContinuousRelease 43 kB/s | 3.0 kB 00:00
CentOS Linux 8 - Extras 23 kB/s | 1.5 kB 00:00
CentOS Linux 8 - FastTrack 40 kB/s | 3.0 kB 00:00
CentOS Linux 8 - HighAvailability 36 kB/s | 3.9 kB 00:00
CentOS Linux 8 - Plus 24 kB/s | 1.5 kB 00:00
CentOS Linux 8 - PowerTools 50 kB/s | 4.3 kB 00:00
Extra Packages for Enterprise Linux Modular 8 - x86_64 13 kB/s | 9.2 kB 00:00
Extra Packages for Enterprise Linux 8 - x86_64 24 kB/s | 8.5 kB 00:00
Metadata cache created.
After updating yum database, We can install opensmtpd using dnf by running the following command:
sudo dnf -y install opensmtpd
Install opensmtpd on CentOS 8 Using yum
Update yum database with yum using the following command.
sudo yum makecache --refresh
The output should look something like this:
CentOS Linux 8 - AppStream 43 kB/s | 4.3 kB 00:00
CentOS Linux 8 - BaseOS 65 kB/s | 3.9 kB 00:00
CentOS Linux 8 - ContinuousRelease 43 kB/s | 3.0 kB 00:00
CentOS Linux 8 - Extras 23 kB/s | 1.5 kB 00:00
CentOS Linux 8 - FastTrack 40 kB/s | 3.0 kB 00:00
CentOS Linux 8 - HighAvailability 36 kB/s | 3.9 kB 00:00
CentOS Linux 8 - Plus 24 kB/s | 1.5 kB 00:00
CentOS Linux 8 - PowerTools 50 kB/s | 4.3 kB 00:00
Extra Packages for Enterprise Linux Modular 8 - x86_64 13 kB/s | 9.2 kB 00:00
Extra Packages for Enterprise Linux 8 - x86_64 24 kB/s | 8.5 kB 00:00
Metadata cache created.
After updating yum database, We can install opensmtpd using yum by running the following command:
sudo yum -y install opensmtpd
How To Uninstall opensmtpd on CentOS 8
To uninstall only the opensmtpd package we can use the following command:
sudo dnf remove opensmtpd
opensmtpd Package Contents on CentOS 8
/etc/opensmtpd
/etc/opensmtpd/smtpd.conf
/etc/pam.d/smtp
/etc/pam.d/smtp.opensmtpd
/usr/bin/mailq
/usr/bin/mailq.opensmtpd
/usr/bin/newaliases
/usr/bin/newaliases.opensmtpd
/usr/bin/smtp
/usr/lib/.build-id
/usr/lib/.build-id/2d
/usr/lib/.build-id/2d/52a5688a0148f560b25ea582f6835665c46871
/usr/lib/.build-id/39
/usr/lib/.build-id/39/c376751ec8de8a644b0a91267430f21db128bb
/usr/lib/.build-id/59
/usr/lib/.build-id/59/9c7b62655308be3142a2808ad550cbdc133695
/usr/lib/.build-id/95
/usr/lib/.build-id/95/718d7fa3872c0c40ccb0c2d0036736aa3ac06f
/usr/lib/.build-id/a7
/usr/lib/.build-id/a7/58b58b657f9e0754b7a03f072ad4c73fdeb037
/usr/lib/.build-id/ae
/usr/lib/.build-id/ae/f4828c163dd059477a0e8b8a3810aee78aa3eb
/usr/lib/.build-id/af
/usr/lib/.build-id/af/b083da036eadde02720be703d8bcc7276a9579
/usr/lib/.build-id/be
/usr/lib/.build-id/be/9db6b253a4b9dbfa8219c2416b2f7c26960e08
/usr/lib/.build-id/d3
/usr/lib/.build-id/d3/196898655efab93c6fedc34b1b8f86e1524d03
/usr/lib/.build-id/da
/usr/lib/.build-id/da/46ebf9583eebc3bdd1749f451d13e4a9a8b8fe
/usr/lib/sendmail
/usr/lib/systemd/system/opensmtpd.service
/usr/libexec/opensmtpd
/usr/libexec/opensmtpd/encrypt
/usr/libexec/opensmtpd/lockspool
/usr/libexec/opensmtpd/mail.lmtp
/usr/libexec/opensmtpd/mail.local
/usr/libexec/opensmtpd/mail.maildir
/usr/libexec/opensmtpd/mail.mboxfile
/usr/libexec/opensmtpd/mail.mda
/usr/sbin/makemap
/usr/sbin/makemap.opensmtpd
/usr/sbin/sendmail
/usr/sbin/sendmail.opensmtpd
/usr/sbin/smtpctl
/usr/sbin/smtpd
/usr/share/doc/opensmtpd
/usr/share/doc/opensmtpd/CHANGES.md
/usr/share/doc/opensmtpd/README.md
/usr/share/licenses/opensmtpd
/usr/share/licenses/opensmtpd/LICENSE
/usr/share/man/man1/mailq.1.gz
/usr/share/man/man1/mailq.opensmtpd.1.gz
/usr/share/man/man1/newaliases.1.gz
/usr/share/man/man1/smtp.opensmtpd.1.gz
/usr/share/man/man5/aliases.5.gz
/usr/share/man/man5/aliases.opensmtpd.5.gz
/usr/share/man/man5/forward.5.gz
/usr/share/man/man5/smtpd.conf.5.gz
/usr/share/man/man5/table.5.gz
/usr/share/man/man8/makemap.8.gz
/usr/share/man/man8/makemap.opensmtpd.8.gz
/usr/share/man/man8/newaliases.opensmtpd.8.gz
/usr/share/man/man8/sendmail.8.gz
/usr/share/man/man8/sendmail.opensmtpd.8.gz
/usr/share/man/man8/smtp.8.gz
/usr/share/man/man8/smtp.opensmtpd.8.gz
/usr/share/man/man8/smtpctl.8.gz
/usr/share/man/man8/smtpd.8.gz
/usr/share/man/man8/smtpd.opensmtpd.8.gz
/var/empty/smtpd
References
Summary
In this tutorial we learn how to install opensmtpd on CentOS 8 using yum and dnf.