Sounds like connecting to the network ran ntp via /etc/network/if- up.d/ntpdate, causing time to be synced and set an hour or so back (check logs?). Which would in turn be reason for sudo to complain about timestamps being too far in the future.
Man page only specifies "Timestamps with a date greater than current_time + 2 * TIMEOUT will be ignored and sudo will log and complain. This is done to keep a user from creating his/her own timestamp with a bogus date on systems that allow users to give away files". Apparently the timestamp is only ignored for as long as it's too far off, but not removed or invalidated. With timeout at (iirc) 15 minutes, it would take about 19 minutes in your situation for sudo to "start working again" without new password. -- sudo: timestamp too far in the future https://launchpad.net/bugs/76639 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
