I'm managing two D6 (6.29) sites that keep missing their homepage. It has been happening 2 to 3 times in a 24 hour period with regularity. I have contacted the hosting company who has been monitoring the servers. I have implemented a monitoring system myself and now aware of how often they go down. What is happening is anonymous users are seeing a 404 page not found. If I login in, I see the front page. If I save the site information page, without changing anything it comes back. If I run cron, it comes back. If I flush the cache it comes back. Both sites use the default /node for the homepage.