In this post I explain how I installed the IRC client Quassel on my CentOS 7 server.

What is Quassel?

Quassel is an IRC client with both a server and client component. It is possible to install quassel-core (the server component) locally on your laptop and then connect quassel-client to localhost. However, that pretty much defeats the purpose of Quassel, and you might as well run something like HexChat in that case.

The advantage with Quassel’s server-client model is that the client can be offline while the server stays connected and acts as a bouncer. You appear as constantly connected and when the client reconnects to the core the chat history is retrieved.


Quassel is not available in CentOS’s default repositories. However, it is available in EPEL, which stands for “Extra Packages for Enterprise Linux,” as quassel-core.

To install EPEL on CentOS, execute the following command:

yum install epel-release

Install Quassel Core

Then install Quassel Core on the server:

yum install quassel-core

Install PostgreSQL

For PostgreSQL support we also need to install the following two packages:

yum install postgresql-server qt-postgresql

Create a new user

As explained on, we need to create a user for running Quassel:

useradd -r -U quassel
mkdir /srv/quassel
chown -R quassel:quassel /srv/quassel

Set up the database

On the page there are a set of instructions explaning how to set up a PostgreSQL database for Quassel:

su - postgres -c initdb
systemctl start postgresql.service
su - postgres -c "createuser quassel"
su - postgres -c "createdb --owner=quassel --encoding=UTF8 quassel"

su - quassel -c "quasselcore --select-backend=PostgreSQL --configdir=/srv/quassel"

# If creating a user fails, run the following:
su - quassel -c "quasselcore --add-user"

In addition I also had to add the following three lines to the file /var/lib/pgsql/data/pg_hba.conf:

local   quassel         quassel                                 md5
host    quassel         quassel            md5
host    quassel         quassel         ::1/128                 md5

Otherwise I would get an authentication error when executing

quasselcore --select-backend=PostgreSQL --configdir=/srv/quassel

as the quassel user. Do not forget to also restart Postgres if you add those lines.

Generate a certificate

For us to be able to connect to our Quassel core over SSL, we need to generate a self-signed certificate. Do that by running the following command:

openssl req -x509 -nodes -days 365 -newkey rsa:4096 -keyout /srv/quassel/quasselCert.pem -out /srv/quassel/quasselCert.pem

Create a systemd unit file

Furthermore as explained on, we need to create a systemd unit file. Mine at /etc/systemd/system/quassel.service looks like this:

Description=Quassel Core

ExecStart=/usr/bin/quasselcore --require-ssl --configdir=/srv/quassel


Start Quassel core

Finally start Quassel with the following two commands:

systemctl start quassel
systemctl enable quassel

Then see if it is running with the following command:

systemctl status quassel

Install the Quassel client

Now, on your laptop, install the Quassel client. I am running Fedora and I installed it with:

dnf install quassel-client

Then connect to the IP address of your server and a username and password of your choice.