I used to work with David Mills, back long ago. He was one of the original Internet Buzzards, a really great guy. One of the many things he invented was NTP.
He would get pretty exercised about keep-alives. Felt that it was not the business of TCP to make these kinds of decisions. I can't remember if he actually called them an abomination, but at the same time, one was left with the feeling that he might have. I never fully appreciated his argument until John DeGood described ham radio internet tcp sessions (this is also long ago) that would halt for days, then come back to life. That's pretty neat, and it can be hard if you are depending on keepalives. Just about any value you pick will be wrong. So, yeah, they're out there and I guess nowadays everyone does them. Whether they are a good idea is somebody else's guess, I suppose. I note that today I slept my mac several times during this workshop and my ssh session was always there when I opened the lid again. That's nice. ron
