The link for How DNS Works takes you to the article:
Lenovo, Google websites hijacked by DNS attacks
Hmm… that doesn’t sound right 
Sorry about that! I have forwarded on the typo to the curriculum team! It looks like the article is still relevant, but that certainly isn’t an accurate description of the article that it links to.
Thanks for catching it!
The article that it linked to was great and interesting. I just told my students to go with it!