Default NTP server on Arch Linux for rPI 2

Question

I have a RPi 2 running Arch Linux (Linux 4.1.6-2-ARCH), I checked and it does not use ntpd but systemd-timesyncd.

I quote from timesyncd wiki page

To add time servers or change the provided ones, uncomment the relevant line and list their host name or IP separated by a space [...] :

#NTP=

#FallbackNTP=0.arch.pool.ntp.org 1.arch.pool.ntp.org 2.arch.pool.ntp.org 3.arch.pool.ntp.org

As this variables are commented by default, what is the default ntp server used on Arch?

The wiki cites also that ntp servers can be provided by other services like systemd-networkd or via DHCP, however when I check networkd service status I see that it's not loaded, and I don't use dhcp.

Answer 1

So the first thing to note is that netctl and systemd-networkd are two different systems for managing your network. Things get confusing when trying to use both. I've completely switched to just using systemd and I've found it keeps things much easier when it comes to configuring and troubleshooting problems. YMMV.

You state in the comments that systemd-timesyncd isn't running, you can confirm this by running:

> systemctl status systemd-timesyncd.service
* systemd-timesyncd.service - Network Time Synchronization
   Loaded: loaded (/usr/lib/systemd/system/systemd-timesyncd.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2015-11-06 12:03:40 PST; 4h 28min ago
     Docs: man:systemd-timesyncd.service(8)
 Main PID: 150 (systemd-timesyn)
   Status: "Synchronized to time server 4.53.160.75:123 (2.arch.pool.ntp.org)."
   CGroup: /system.slice/systemd-timesyncd.service
           `-150 /usr/lib/systemd/systemd-timesyncd

Nov 06 12:03:40 beagle systemd[1]: Starting Network Time Synchronization...
Nov 06 12:03:40 beagle systemd[1]: Started Network Time Synchronization.
Nov 06 12:03:48 beagle systemd-timesyncd[150]: Network configuration changed, trying to establish connection.
Nov 06 12:03:48 beagle systemd-timesyncd[150]: Network configuration changed, trying to establish connection.
Nov 06 12:03:50 beagle systemd-timesyncd[150]: Network configuration changed, trying to establish connection.
Nov 06 12:04:19 beagle systemd-timesyncd[150]: Synchronized to time server 4.53.160.75:123 (2.arch.pool.ntp.org).

If this shows different output indicating systemd-timesyncd isn't responsible for your NTP, then try searching the journal for what is:

> journalctl -b | grep -i ntp
Nov 06 12:03:38 beagle kernel: Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
Nov 06 12:04:19 beagle systemd-timesyncd[150]: Synchronized to time server 4.53.160.75:123 (2.arch.pool.ntp.org).

In my case, systemd-timesyncd is controlling NTP so that shows up here. If netctl is doing it in your case, you might see that show up instead.

As to the original question of what are the default servers, assuming you are using systemd-timesyncd (the default in Arch), the NTP defaults will be the commented out line you linked, which I'll repeat here:

> grep Fallback /etc/systemd/timesyncd.conf
#FallbackNTP=0.arch.pool.ntp.org 1.arch.pool.ntp.org 2.arch.pool.ntp.org 3.arch.pool.ntp.org

The confirmation of these being the defaults is seen in the manpage for timesyncd.conf, which states:

Default configuration is defined during compilation, so a configuration file is only needed when it is necessary to deviate from those defaults. By default the configuration file in /etc/systemd/ contains commented out entries showing the defaults as a guide to the administrator.