Non responding server

dns

#1

Hi all.

I’m developing an embedded device for my company, and trying to embed sntp client on it.

All works fine except from when the server I set is “pool.ntp.org”.

the resolved ip from the given name server would be 109.226.40.40 and that address is not respond, not even to ping request.

Is this problem at your side? Or DNS problem? Or server problem?

Thank you.


#2

The server admin may block unwanted ip ranges. The pool itself does not guarantee availabity of any single server to any single client; it only maintains a list of servers looks like available from the pool monitor’s point of view.

Besides, since you are doing this for your company, you should apply vendor zone for your product.
https://www.pool.ntp.org/vendors.html
Usage of pool.ntp.org as default for commercial product is against recommendation.


#3

Also a query to any of the pool hostnames should return 4 separate IP addresses. So if one is down you could step to the next.


#4

Seems to work at least now from at least here:

  $ ntpdate -qu 109.226.40.40
  server 109.226.40.40, stratum 2, offset -0.002074, delay 0.11153
   6 Oct 16:47:58 ntpdate[24472]: adjust time server 109.226.40.40 offset -0.002074 sec

Note that this is only one of the 2000+ pool servers in the pool. As mentioned above, you should apply for a vendor zone if you are thinking about using the pool for your NTP needs, especially for an embedded device.

I’ll add that at least my servers tend to receive way too many ICMP echo requests (pings), so I’ve ended up blocking ping except those that originate from my other servers. That server does not seem to respond to ping from my location either.


#5

thank you all for replying.
it seems like this address is not anabled to receiv packet from, on my comapnys’ servers.

chacke by enabling hotspot on phone and all works fine.

thank you all.

Assaf.