First of all, if you are here because Citrix is not working in Ubuntu, that’s because you are probably using the wrong web browser such as Google Chrome. Start with Firefox.
Now if you are in Firefox and after a minute you get the following error message [You have not chosen to trust “Entrust.net Secure Server Certification Authority, the issuer of the server’s security certificate.”], then this means you have to copy the following certificates to your cacerts folder.
Usually, the folder should be under /home/user/Documents/ICAClient/linuxxNN/keystore/cacerts, however it may not be there. Per my experience, it is actually in my /opt/Citrix/ICAClient/keystore/
If you are having trouble locating your folder, simply execute the following command in your terminal to find the folder:
find / -iname 'cacerts' -type d
Once you locate the folder, download all the Root Certificates available at: http://www.entrust.net/developer/index.cfm. When you are there and you click on Download Root certificates, select the radio button that says “Personal Use”. To download, right click on the links and “Save As” to the directory of your choice. In my case, I created one called “Entrust Certificates”. Then I copied all the ones I downloaded over to my folder by opening a terminal window and navigating to the directory where I stored my certificates.
cp entrust_2048_ca.cer /opt/Citrix/ICAClient/keystore/cacerts cp entrust_ev_ca.cer /opt/Citrix/ICAClient/keystore/cacerts cp entrust_g2_ca.cer /opt/Citrix/ICAClient/keystore/cacerts cp entrust_ssl_ca.cer /opt/Citrix/ICAClient/keystore/cacerts
After that, Citrix started without a problem. Also, please note that if you decide to add the certificates via Firefox > Preferences > Certificate > Authorities, it will NOT have an effect. Also, I am using Ubuntu 10.4 and Citrix Receiver 12