Score:1

DHCP NTP Server Option 042 not propagated by Windows Server 2016

ph flag

I am trying to make NTP server settings available to our non-Microsoft devices on local wired and wireless network. Obviously, they don't know how to use MS AD time info from domain controller.

Our Windows Server 2016 is serving as DHCP server for both the local wired and wireless network. I have configured 042 NTP Servers option in DHCP Manager in both "Server options" and "Scope options", but analysis with Wireshark doesn't show that NTP Servers information option is present in DHCP Offer and DHCP ACK packets.

This information was in a few DHCP Offer packets just after configuring DHCP Option 042, but it had disappeared since.

Is there anything that I am missing?

DHCP manager window

Thank you.

Now it sometimes works, and sometimes doesn't. Which may indicate that I did the right thing, but missed something to make it reliable?

Wireshark message 1 - NTP servers aren't listed Wireshark message 2 - NTP servers correctly listed

Thank you again

Marvin

P.S.

The time server information is still only in DHCP Offer messages and not in DHCP ACK messages. Is that normal? Thank you.

Score:1
ph flag

Apparently, the mystery appears to be solved!

Window 2016 DHCP server advertises time servers only when it is requested in DHCP Discover message, like this one:

DHCP Disover in Wireshark

So, only our WAP asked for NTP server information, since PCs get their time updated from AD. I guess this way both systems can coexist without interference and complications.

Thanks for your thoughts and attention!

P.S.

And yes, NTP server information is present in DHCP ACK messages as well, when requested in DHCP Request, as shown in this capture:

DHCP Request with NTP server parameter request

Marvin

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