ntpd (package: ntp 4.2.0-r2) is currently started after the network. This is fine for permanent network connections, but is incorrect for part-time connections such as PPPoE. Once was a time when ntpd would restore connections to its time servers if the network connection was dropped and restored. However, it would only do so if it was was started *before* the connection to the Internet was established. Version 4.2.0 appears to no longer support this undocumented feature. With 4.2.0, if network connectivity is lost, ntpd's "when" counters continue to count past their poll time and keep going ... to infinity and beyond. ntpd does not recover when the network connection is restored. Gentoo's current configuration insures that ntpd will lose sync forever if the network connection is brought down. Reproducible: Always Steps to Reproduce: 1. Insure that network is down and ntpd is not running. 2. adsl-start 3. /etc/init.d/ntpd start 4. Wait for ntpd to sync. Check with "ntpq -p". 5. adsl-stop 6. Wait for ntpd's "when" counters to exceed the poll interval ("ntpq -p" again). (Actually, I'm not sure about this -- you may not have to wait at all.) 7. adsl-start 8. See how ntpd is doing ("ntpq -p" again). Actual Results: ntpd fails to sync with any of its time servers. "When" counters just keep on counting. Expected Results: Should sync. For this scenario, /etc/init.d/ntp-client is similarly ineffectual. My solution was to append the following to "/etc/ppp/if-up.local": [ "$1" == "ppp0" ] && [ -x /etc/init.d/ntpd ] && /etc/init.d/ntpd start and this to "/etc/ppp/ip-down.local": [ "$1" == "ppp0" ] && [ -x /etc/init.d/ntpd ] && /etc/init.d/ntpd stop These modifications are rather specific to my installation (e.g. "ppp0" as Internet connection) and also assumes that if the ntpd package is installed, then ntpd should be started. Also required is that ntpd not be started with the rc-update mechanism. I don't know how well these suggestions fit into Gentoo's package architecture, but this is what currently works for me.
Found this: http://bugzilla.ntp.org/show_bug.cgi?id=51 Confirms my situation, and recommends against the "trick" of starting ntpd before the network. Their script is more sophisticated than my solution, though the issue of invoking the script at the right time remains.
although we could try to implement those scripts partially in our network init.d scripts, that would 'work' only for the people who use those methods of connecting to the net ... there are many more ways, and not everyone uses them ... so really the only 'proper' fix is for ntpd guys to find something :/
