Andrew Zbikowski wrote: >> Any thoughts on flushing the old ip address if indeed that's the case? > > If DNS information is persisting after a reboot I can think of three > possible causes: > > #1: You have a static mapping for security.ubuntu.com in your /etc/hosts file. Nope, it's not in there. > #2: Your DNS server is holding cached records. This could be proper, > as an update to DNS may have been required but the TTL on the previous > information hasn't yet expired, or the DNS server could have it's own > static map or needs a kick in the seat. If that were the case, wouldn't I see the same stale information when I run host or nslookup from the command line as well? As it is these are giving me the correct info, but aptitude and apt-get are not. > #3: security.ubuntu.com may be in a round robin DNS configuration for > load balancing and one of the servers in the round robin is down. I think you're right about this, but for some reason it's just not letting go of the old association. I'll try filing a bug report. -Steve