Comment 24 for bug 33505

Another use case: I use a DSL modem/router at home which intercepts HTTP requests and returns error pages informing me of the status of my internet connection when my DSL connection goes down. I personally think this is reasonable behaviour, but even if you disagree, the point is that this is a default configuration of many such devices and just telling people to reconfigure their routers is not a very user-friendly solution. Apt should be more robust. Instead, if cron-apt runs when my connection happens to be down, invalid data may get cached in /var/lib/apt/lists, meaning that when the connection is back up I get the BADSIG error when I next try to fetch updates. As Wayne Scott says above, bad data should be detected and flushed from the cache.