My DSL connection runs slow sometimes...

What can I run from my-side of it (type-in at the terminal)
to test it and maybe even learn a thing or two about it? :)

Recently it was "down" and Qwest said it was my "firewall".
Yeah right, a couple days later it started working again. ;)

Since then, it is sometimes slower than a YouTube video.
It acts as if I'm sharing it?
I'd like to know/understand it instead of guessing at it. ;)

Got any "good;)" suggestions for where and what to read? :)

Alvin in AZ
ps- my Assembly Language/Linux geek of a son can and will
"fix" it for me but I never learn anything that way :/