way nifty...
It would be really handy/fun/interesting to attach user's notes to each section. My paper copy is getting extra ink all the time. Things like exclamation points, big stars, arrows, comments, traps. Clarifications on some concepts for new 'admins' in 'small' networks. Even casual rebuttal - necessary for gems like;
"A zone contains the domain names that the domain with the same domain name contains, except for domain names in delegated subdomains."
(p22)
To this day I still have to read that three or four times.

As far as I can tell it's an accurate statement but part of me still wants to run it through babel and see if it makes more sense.
As for sendmail, I thought I pretty much had a handle on it 'til I saw the O'Reilly volume on the shelf at the bookstore. "Hey." said self. "That's a pretty big book for a pretty straighfoward application." So I bought it. That was a year ago and it still scares me whenever I open it.