NTP doesn't update DHCP client configuration

[Paul Smith]

Binary package hint: ntp

The NTP package comes with /etc/dhcp3/dhclient-enter-hooks.d scripts to enable the local system to discover its NTP servers via DHCP, which is a very common configuration in an Enterprise setting. This is good!

However, the default /etc/dhcp3/dhclient.conf file does NOT request the NTP servers from the DHCP server; the request entry says:

request subnet-mask, broadcast-address, time-offset, routers,
        domain-name, domain-name-servers, host-name,
        netbios-name-servers, netbios-scope;

Note that the "ntp-servers" option is not present here.

The NTP package needs to have code to update the dhclient.conf file to request those servers be delivered, otherwise the DHCP entry hook scripts in /etc/dhcp3/dhclient-enter-hooks.d are useless.

I suppose an alternative would be to change the default "request" entry in the dhclient package itself, to add the ntp-servers option?

[Paul Smith (psmith-gnu)]

If it's decided that the nis package cannot update dhclient.conf due to packaging rules, then this bug is a duplicate of https://bugs.launchpad.net/bugs/74164

[Daniel J Blueman (danielblueman)]

As there is no reasonable/robust mechanism of updating the /etc/dhcp3/dhclient.conf, I believe requesting 'ntp-servers' always is the best practical way.
 - this needed when your DHCP server hands out only what is requested
  -> eg Microsoft DHCP service (and unlike ISC DHCPD)
 - if the option is available, it is stored in the lease
 - if 'ntp' is installed, we get NTP working as it should
 - if it's not installed, no problem!

This clearly presents an integration issue in certain environments (eg corporate), so addressing it is a positive move!

[Steve Langasek (vorlon)]

Thank you for taking the time to report this bug and help to improve Ubuntu.

Actually, the current default version of /etc/dhcp3/dhclient.conf *does* request the NTP servers; this was changed in dhcp3 3.0.5-2, and apparently reintroduced in dhcp3 3.1.1-5ubuntu8 for the Ubuntu 9.04 release. So I'm marking this bug as fixed.