two IPs in one?

Question

how can run two different dsl connections on one server and if [yes], do I need to add another ethernet card ?

Answer 1

Well, you can but the computer will ONLY USE ONE at a time.
So you can run your web server on one IP and your ftp server pr email server on the other etc In this case you will need two nics and bind the services wanted to each card. You can't and won't end up with combined lines.

You might be better off using a dual wan router which would auto load balance for your entire network!

If you are attempting to increase the total download/upload speed the two dsl lines will need to be BONDED at the ISP end also.