NTP server

[Justinh]

While updating the firmware on my RT-AX86U Pro, I saw my NTP server was set to north-america.pool.ntp.org, and I pinged it to see if it was still valid. No ping response, so I went searching and found that 0.north-america.pool.ntp.org is supposed to be valid. And that leads to some questions, of course ...

1) How important is having the NTP server configured in the router? What are the impacts of not having it?
2) How do I know if the NTP server is valid and that the router is getting what it needs from the server?
3) I poked around in the System log and found a few of "crond[2561]: time disparity of 1199203 minutes detected" - is that a concern or indication of failed NTP checks?

 

[ColinTaylor]

DNS lookups for north-america.pool.ntp.org and 0.north-america.pool.ntp.org should both work. Although in some cases a specific IP address returned by DNS may have gone offline before the DNS records were updated.

1. The router having a reasonably correct time is necessary if you want the router to use things like DNS-over-TLS.
2. See my first sentence.
3. That message normally appears just after the router has correctly set the time from the NTP server when booting up.

 

[Justinh]

Thanks, Colin.
To clarify my second question, I'm not asking what is a particular valid server host, but how can I tell that the server I am using is valid. E.g., if I put in burgerking.com what will the router do to tell me that is not a good server?

 

[bennor]

While updating the firmware on my RT-AX86U Pro, I saw my NTP server was set to north-america.pool.ntp.org,

Not sure what firmware you updated from, or if you previously changed the NTP server, but when I updated to 3.0.0.6.102_37421 I performed a hard factory reset. Post hard factory reset my NTP server on a RT-AX86U Pro was set to pool.ntp.org.



Edit to add: Also, I am getting a ping response from north-america.pool.ntp.org on a Windows 11 PC:



And a north-america.pool.ntp.org ping response using the router's network tools:

 

[dave14305]

Good reference about all the pool options available, but some of it makes less sense without a proper ntp.conf that the firmware doesn't use.

pool.ntp.org: How do I setup NTP to use the pool?

www.ntppool.org

 

[Justinh]

pool.ntp.org: How do I setup NTP to use the pool?

www.ntppool.org

Right, I had a similar thought.

I tried north-america.pool.ntp.org again and got a response this time (faster than from 0.*), but I tried again like 1 minute later and 'request timed out' again. I think I'll abandon it if it isn't going to be reliable. Even 0. failed me. So maybe ntp.org is just not reliable.

 

[ColinTaylor]

Ah, I tried

Right, I had a similar thought.

I tried north-america.pool.ntp.org again and got a response this time (faster than from 0.*), but I tried again like 1 minute later and 'request timed out' again. I think I'll abandon it if it isn't going to be reliable. Even 0. failed me. So maybe ntp.org is just not reliable.

There's no obligation for an NTP server to respond to pings, although they usually do.

Remember that a lot of the servers in the "pool" are run by hobbyists on their home equipment. I've written here in the past that I've found ntp.org servers unreliable. I've since switched to time.google.com and time.windows.com.

 

[Justinh]

Remember that a lot of the servers in the "pool" are run hobbyists on their home equipment. I've written here in the past that I've found ntp.org servers unreliable.

I did not know. Thanks for that.

I just set mine to time-b-b.nist.gov.

 

[dave14305]

I just set mine to time-b-b.nist.gov.

Why? Per the NIST site, it's bad practice to hardcode a specific server from their pool.

NIST Internet Time Service