Comments on: Configuring Windows 2003 / XP SP2 to Use IOS NTP Server

By: Peter Sprokkelenburg

Peter Sprokkelenburg — Tue, 29 Mar 2011 22:09:02 +0000

Yeah, I”m still seeing things cut of on the article… had to view it in source to get the full command…

By: Greg Ferro

Greg Ferro — Mon, 16 Aug 2010 10:37:39 +0000

I’ll see what I can do.

By: Tim Smith

Tim Smith — Mon, 16 Aug 2010 06:08:01 +0000

Hey Greg,

FYI, some lines of content scroll out of the frame in your main content (see the line containing “w32tm /config /manualpeerlist…”). While there’s a horizontal scrollbar down the very bottom of the frame, it’s not immediately obvious. Especially if you’re copy and pasting (or manually typing) command-line examples…

(This is with a browser maximized at 1440px horizontal resolution.)

By: Ivan

Ivan — Wed, 18 Mar 2009 00:13:37 +0000

Thanks a lot for your input!!! My system is working great after following your document line by line.

Thanks again!!
Ivan

By: I-BLOG » Blog Archive » NTP Server on Cisco ASA 5500

I-BLOG » Blog Archive » NTP Server on Cisco ASA 5500 — Sat, 06 Sep 2008 15:46:06 +0000

[...] should do; now for your internal client machines, point them to ASA for time synchronization. http://etherealmind.com/2008/06/10/ios-configure-windows-2003-xp-use-ntp-server-sync-time-clock-rout... Look at the above as reference. Technorati Tags: Cisco ASA,NTP [...]

By: BenG

BenG — Sat, 05 Jul 2008 12:59:52 +0000

Greg -

The “ntp master” command is only going to do something if you loose your external synchronization. By default, it has a stratum value of 7. Unless your external sources have a REALLY low stratum value, “ntp master” will never do anything. If you have two core devices, you may want to investigate “ntp peer” between the two. This will allow both to sync to each other should they loose their better valued upstream source.

By: Greg Ferro

Greg Ferro — Tue, 10 Jun 2008 11:13:15 +0000

From a security perspective, you should always have an internal clock source for your network. Thus ‘ntp master’.

Therefore I usually make the two ‘most’ core switches the NTP master for the entire network. Then sync these two against an external time source (ready for an atomic clock in the future). Thus ‘ntp server’.

Firewall rules for pool.ntp.org are problematic in some companies since they may only allow IP addresses in firewall rules. Also, trusting an external clock is broadly regarded as insecure.

Hard to find middle ground really.

By: Michael

Michael — Tue, 10 Jun 2008 07:54:37 +0000

why NTP master? i think you need NTP master on IOS only if you do not have a reference clock but you do if you use a ntp server…

BTW you might want to point out everybody can sync to pool.ntp.org

MGK