I'd say one of the lessons is that even a supposedly well-standardised system sees hundreds of implementations (or more!) then the accumulated bug baggage can still make it hacky with per-platform code. For comparison consider web browsers, which although are far better these days than they used to be, between just Chrome, Firefox, IE and Safari there's a bunch of quirks and platform-specifics, so I can imagine worldwide TCP deployments are "interesting".
Where possible hacks should be applied only where necessary, e.g. the specific software versions affected only, and exclude fixed versions. Then hopefully in the long run the old buggy versions die out and the hack can be removed... but as the article says, over a network it's not always possible to identify when to apply a hack.
Where possible hacks should be applied only where necessary, e.g. the specific software versions affected only, and exclude fixed versions. Then hopefully in the long run the old buggy versions die out and the hack can be removed... but as the article says, over a network it's not always possible to identify when to apply a hack.