How To Install sslh on CentOS 8
Introduction
In this tutorial we learn how to install sslh on CentOS 8.
What is sslh
sslh accepts connections on specified ports, and forwards them further based on tests performed on the first data packet sent by the remote client. Probes for HTTP, SSL, SSH, OpenVPN, tinc, XMPP are implemented, and any other protocol that can be tested using a regular expression, can be recognized. A typical use case is to allow serving several services on port 443 (e.g. to connect to ssh from inside a corporate firewall, which almost never block port 443) while still serving HTTPS on that port. Hence sslh acts as a protocol multiplexer, or a switchboard. Its name comes from its original function to serve SSH and HTTPS on the same port.
We can use yum or dnf to install sslh on CentOS 8. In this tutorial we discuss both methods but you only need to choose one of method to install sslh.
Install sslh 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 sslh using dnf by running the following command:
sudo dnf -y install sslh
Install sslh 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 sslh using yum by running the following command:
sudo yum -y install sslh
How To Uninstall sslh on CentOS 8
To uninstall only the sslh package we can use the following command:
sudo dnf remove sslh
sslh Package Contents on CentOS 8
/etc/sslh.cfg
/etc/sysconfig/sslh
/usr/lib/.build-id
/usr/lib/.build-id/68
/usr/lib/.build-id/68/724870d4b90e0be0fdbc45957c9b75ec6cf830
/usr/lib/.build-id/eb
/usr/lib/.build-id/eb/597a353f365e6054247f3579a01920a80c695e
/usr/lib/systemd/system/sslh.service
/usr/lib/systemd/system/sslh.socket
/usr/sbin/sslh
/usr/sbin/sslh-select
/usr/share/doc/sslh
/usr/share/doc/sslh/ChangeLog
/usr/share/doc/sslh/README.md
/usr/share/doc/sslh/example.cfg
/usr/share/licenses/sslh
/usr/share/licenses/sslh/COPYING
/usr/share/man/man8/sslh.8.gz
References
Summary
In this tutorial we learn how to install sslh on CentOS 8 using yum and dnf.