Server software used to generate CSR

I’m trying to install a certificat and from various posts here and other information I see I might be out of luck trying to have a free certificate without my own domain. Well, I’m trying anyway and Comodo asks which server software was used to generate the CSR.
Couldn’t find the answer anywhere, can anyone help me? Thanks in advance.

OpenSSL was used to generate the CSR. But if they ask for which web server software you’re using, you should enter Apache.