It looks like there are two options for providing network time settings to a DHCP client; option 004 and option 042. The description for 004 is "Time Server", while 042 specifies NTP. Is there a reason to use one or the other, or is it just vendor preference? If the client uses option 042, is the time offset in option 002 still used?
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From a Google search, first result:
Option 004 specifies servers that provide TIME/ITP (as per RFC 868). This is not a recommended protocol/service in a Windows environment.
Option 042 specifies servers that provide NTP/SNTP (RFC 1769). This is the preferred time service in a Windows environment (assuming the absence of Active Directory which maintains the time on your behalf).
Niko
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Unfortunately that site is unreadable unless your referer is from Google. – Zoredache May 12 '09 at 20:57
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Rats! Did not realized, thank you. Link updated. – May 12 '09 at 21:05
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1Thanks. I wound up answering the last question myself. The (non windows) device that I'm concerned with will look for option 042 then 004, and will use 002 for GMT offset. – TimM May 13 '09 at 14:58
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Updated the link, so it will go directly to the source, without the need of going to Google. – May 15 '09 at 11:20
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111 years later and this question is the first result. Well done. – kaiser May 12 '20 at 22:36
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The RFC 868 "time" service as specified by Option 4 is pretty much obsolete and only has 1s resolution.
Modern networks should always use NTP (Option 42).
Alnitak
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