New to Slackware

So, I've got an old machine that's a piece of junk. I've tried to install a few distro's on it, finally settling with debian, just to run a dedicated web, ftp, and...maybe a game server or two.

But I was running into some issues there, and I decided I'd run slackware instead.

Got everything installed and up, BUT

wget http://randomwebsite.com/index fails with the following response:
Resolving randomwebsite.com... failed: Temporary failure in name resolution.

However, wget ###.###.#.#/index.html works.

Any way to fix this so I don't need to IP-lookup every time I need to install software?