1. Modifying the hosts file manually

Firstly run nano /etc/hosts as root/with sudo.

When you’ve got it open, paste the following at the bottom:

95.216.193.66 osu.ppy.sh c.ppy.sh c1.ppy.sh c2.ppy.sh c3.ppy.sh c4.ppy.sh c5.ppy.sh c6.ppy.sh ce.ppy.sh a.ppy.sh s.ppy.sh i.ppy.sh

CTRL+X and then Enter to save the file.

2. Installing the certificate

Download the certificate by clicking here

Open the Internet Explorer configuration by running wine control.

Double click the Internet Settings icon, navigate to the Content tab, then click the Certificates… button.

Click on Import, then Next.

Click Browse… then select the Gatari certificate.

Click Next.

Select Place all certificates in the following store, and click Browse.

Select Trusted Root Certification Authorities, and click Ok.

Click Next, Finish.

You should get a message saying The import was successful.

After that is done, you can start the client up, and log in with your Gatari credentials.