DHCP Scope Options RRS feed

  • Question

  • When configuring DHCP scope options, could someone explain the difference to me between option #4 - Time Server and option #42 - NTP Server.  I do know what an NTP server is and we do have one in our organization, I'm just wondering why and when you would use option #4 as opposed to option #42.

    Thursday, May 27, 2010 3:37 PM


All replies

  • Hello,

    004 specifies servers that provide TIME/ITP (as per RFC 868). This is not a recommended protocol/service in a Windows environment.

    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.


    Peter Rajcinov

    • Proposed as answer by Shifu-TandyBrands Wednesday, June 2, 2010 7:43 PM
    • Marked as answer by Bruce-Liu Friday, June 4, 2010 7:53 AM
    Thursday, May 27, 2010 4:19 PM
  • Just to re-iterate a very important piece of information that Peter pointed out.  If you are running Active Directory in your environment, there is no need to assign Windows Clients that are members of the domain Option 042.  Its built-in to the OS (time service) for the clients to ultimately sync with their PDC emulator's time. 

    Visit: anITKB.com, an IT Knowledge Base.
    Thursday, May 27, 2010 7:07 PM
  • Hi,


    Please refer to this article:


    DHCP Tools and Options





    • Marked as answer by Bruce-Liu Friday, June 4, 2010 7:53 AM
    Friday, May 28, 2010 8:18 AM
  • Thanks for all of the information. I was actually using the NTP server option in DHCP to set time on IP phones not on workstations, but I was wondering what the difference was between the time server option and NTP option.
    Friday, May 28, 2010 8:06 PM
  • I haven't seen any other posts on this topic so I assume that everyone is good?

    Fore more information, I would recommend these links for further reading:

    RFC868 - Time Protocol

    RFC958 - Network Time Protocol (NTP)

    RFC1769 - Simple Network Time Protocol (SNTP)

    Visit: anITKB.com, an IT Knowledge Base.
    • Marked as answer by Bruce-Liu Friday, June 4, 2010 7:53 AM
    Monday, May 31, 2010 2:28 PM