ntpMerlin Display of NTP Requests?

[TonyK132]

Is it possible to dynamically display the requests for the NTP service, kind of like what Diversion does for its requests? I'd like to see what devices are requesting the time, and how often.

 

[chongnt]

I think you can see the session with this

 conntrack -E | grep -E 'port=123.*192.168'

If you install tcpdump from Entware, you can run something like this to see in detail:

opkg install tcpdump

 tcpdump -i br0 -p port 123 and host 192.168

 

[TonyK132]

conntrack seems to work, but so far, all the traffic that it is capturing are UDP. Would I also need to do tcpdump to catch that traffic? Or, is all ntp traffic UDP? Now that I know about conntrack, I'll research how to do more with it. Thanks for getting me started with this.

 

[ColinTaylor]

NTP uses UDP.

RFC 5905: Network Time Protocol Version 4: Protocol and Algorithms Specification

The Network Time Protocol (NTP) is widely used to synchronize computer clocks in the Internet. This document describes NTP version 4 (NTPv4), which is backwards compatible with NTP version 3 (NTPv3), described in RFC 1305, as well as previous versions of the protocol. NTPv4 includes a modified...

datatracker.ietf.org

 

[TonyK132]

NTP uses UDP.

RFC 5905: Network Time Protocol Version 4: Protocol and Algorithms Specification

The Network Time Protocol (NTP) is widely used to synchronize computer clocks in the Internet. This document describes NTP version 4 (NTPv4), which is backwards compatible with NTP version 3 (NTPv3), described in RFC 1305, as well as previous versions of the protocol. NTPv4 includes a modified...

datatracker.ietf.org

Thanks.

 

[TonyK132]

Update: Looks like the conntrack tool also captures TCP packets for port 123.