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RE: Windows Time Synchronization - Best Practices
From: "Gary E. Miller" <gem () rellim com>
Date: Thu, 21 Oct 2004 14:47:25 -0700 (PDT)
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Yo David! On Thu, 21 Oct 2004, Cushing, David wrote:
In my experience NTP will work a lot better for you than Windows Time server.Windows time service uses SNTP.
SNTP is RFC 2030, It says: "SNTP can be used when the ultimate performance of the full NTP implementation described in RFC-1305 is not needed or justified." So right off the bat you know you are sacrificing something. Why settle for less than the best when the best is free? RFC 2030 Continues: "It is strongly recommended that SNTP be used only at the extremities of the synchronization subnet. SNTP clients should operate only at the leaves (highest stratum) of the subnet and ..." "The full degree of reliability ordinarily expected of primary servers is possible only using the redundant sources, diverse subnet paths and crafted algorithms of a full NTP implementation. " Seems to me that rules out using it to connect to the stratum 1 in Seattle, WA from Brazil.
The protocol is robust and you are not dependent on the single point of failure called: time.microsoft.com.Never heard of time.microsoft.com being down or incorrect.
Me neither, but it has been unreachable. Since the original requestor was from Brazil I would think that reachability would be an issue for him. Last time I was monitoring reachability to Brazil there were often outages and bottlenecks to there from the US.
You can use 'net time' or regedit to change it. http://www.microsoft.com/windows2000/docs/wintimeserv.doc
Yeah, but you are still stuck with only ONE server, you are stuck with SNTP and you have almost no way to tell if the time daemon is doing the right thing. With NTP you can designate a local master that gets it's time from a diverse set of sources. It is easy to verify and monitor it's proper functioning. Then you can redistribute it to your local hosts. Contrary to what some may believe, accurate time is very important to security. One time keys, like S/Key, depend on accurate time for their functioning. Any stronge encryption scheme, like IPSec, needs a good clock at both ends to default antireplay attacks When debugging a major system crash, involving many routers, switches, hosts, etc. it is important to have well synced clocks to determine first failure. Stick exchanges require members to use accurate clocks to help prevent fraud. Etc... RGDS GARY - --------------------------------------------------------------------------- Gary E. Miller Rellim 20340 Empire Blvd, Suite E-3, Bend, OR 97701 gem () rellim com Tel:+1(541)382-8588 Fax: +1(541)382-8676 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQFBeC5w8KZibdeR3qURAjDhAJ9kue1cKLMrcVykpL4P03XyCnuB+ACbBL4b mNs+1jkUA470nRGx6ZXPGGA= =9SAK -----END PGP SIGNATURE----- _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
Current thread:
- Windows Time Synchronization - Best Practices Bernardo Santos Wernesback (Oct 19)
- Re: Windows Time Synchronization - Best Practices Gary E. Miller (Oct 19)
- <Possible follow-ups>
- RE: Windows Time Synchronization - Best Practices Richard Stevens (Oct 19)
- RE: Windows Time Synchronization - Best Practices Poof (Oct 19)
- RE: Windows Time Synchronization - Best Practices James Edwards (Oct 20)
- RE: Windows Time Synchronization - Best Practices Phillip R. Paradis (Oct 21)
- RE: Windows Time Synchronization - Best Practices Todd Towles (Oct 19)
- RE: Windows Time Synchronization - Best Practices Keith Pachulski (Oct 19)
- RE: Windows Time Synchronization - Best Practices Cushing, David (Oct 21)
- RE: Windows Time Synchronization - Best Practices Gary E. Miller (Oct 21)
- RE: Windows Time Synchronization - Best Practices Frank Knobbe (Oct 21)
- Re: Windows Time Synchronization - Best Practices Micheal Espinola Jr (Oct 22)
- Virus/Trojan trying to connect external:445 and 212.175.149.149.6667 Murat Bicer (Oct 22)
- Re: Virus/Trojan trying to connect external:445 and 212.175.149.149.6667 darren windham (Oct 22)
- Re: Windows Time Synchronization - Best Practices Gary E. Miller (Oct 24)
- Re: Windows Time Synchronization - Best Practices Andrew Farmer (Oct 25)
- RE: Windows Time Synchronization - Best Practices Gary E. Miller (Oct 21)
- RE: Windows Time Synchronization - Best Practices joe (Oct 22)