I hate firewalls because every firewall between two machines trying totalk to each other is another place for things to go wrong, which meansanother place to check (somehow) when things do go wrong.

Stateless firewalls at least have the grace to have consistent andpredictable behavior; if something is wrong, it is going to be wrong allthe time. Stateful firewalls make your life exciting by varying theirbehavior based on an ever-changing flux of generally unpredictable andinaccessible information, so things can go wrong now and right

Filesystem consistency checkers have historically had three overlappingpurposes:

1. to patch up the damage done when a machine was shut down partway through modifications to the filesystem.

2. to find and fix up problems caused by corrupted disk blocks(whether they're caused by a dying disk, a controller error thatscribbled random data on a track, or whatever).

3. to check for and repair structural errors created by operatingsystem bugs .

Fixing inconsistent filesystems is mostly or entirely obsolete thesedays, due to people moving to journaled filesystems that never