Also known as "a combination that doesn't work".

To be more precise, in my home network I have a gateway PC that's always up (running Slackware 14.1, of course) that serves as a firewall, print server, DNS server, DHCP server, and NTP server for the home network. As part of my DHCP configuration, I tell my clients to use the gateway box as their NTP server; that way, I have only one computer in the network that is talking to the public NTP servers.

Part of the issue is that the NetworkManager developers decided to override standard dhcpcd behavior by not using /lib/dhcpcd/dhcpcd-run-hooks but their own script /usr/libexec/nm-dhcp-client.action (and it isn't obvious to me what exactly nm-dhcp-client.action does even after reading the source). As a result, the various hooks that handle such things under normal dhcpcd operations are not run when dhcpcd is invoked by NetworkManager.

Looking at the NetworkManager implementation for using dhclient, it appears that requests NTP information from the DHCP server and presumably uses it.

I guess the only solution at the moment is to re-write the same *bleeping* code that is in /lib/dhcpcd/dhcpcd-hooks/50-ntp.conf but as a NetworkManager dispatcher script that lives in /etc/NetworkManager/dispatcher.d. That seems like a really stupid waste of time.

If network manager is getting in the way, try wicd.

Well, network manager is part of the official distro while wicd is not.

It is in the /extra directory, so it actually is a part of the distro. Either way for my laptop I always use wicd. For my desktop I use network manager because it is already installed and I don't use wifi. I would say that wicd is the better and more predictable / logical of the two.

We have had this discussion before.

Over the last 3 three years, using two different boxes, in three different locations and four different ISPs, my experience has been just the opposite. NetworkManager does a far better job of making the connections and holding on to them.

I see Arch Linux has a package called networkmanager-dispatcher-ntpd which contains a script (/etc/NetworkManager/dispatcher.d/10-ntpd) that just stops/starts ntpd (no ntp.conf juggling). This blog article doesn't really cover any ntp.conf manipulation either, but I'm sure you could hack something in.

Another option that might be worth looking at is option ntp-servers ip-address [, ip-address... ]; in /etc/dhcpcd.conf.

Well, what I find annoying about the whole thing is that dhcpcd already has ways to handle ntp, routing, and the rest (which is precisely what you would want to have your dhcp client handle for you). The NetworkManager clots decided that they would override that behavior and replace it with (by default) nothing but their own hook framework and then claim "well, it's up to the distro to provide proper hooks".

If the dhcpcd hook scripts aren't run, that won't do any good.