From: Michael Snyder (msnyder@revolutioncomputer.com)
Date: Thu Feb 27 2003 - 18:51:26 GMT-3
Don't forget about commands like
Access-list 1 permit 172.16.0.0 0.0.255.255
Access-list 2 permit 128.105.39.11
Ntp access-group peer 2
Ntp access-group serve 1
That's from page 752 of doyle vol 2
Sample from Page 753
seattle
Ntp authenticate
Ntp authentication-key 10 md5 ntpkey
---------------------------------
tacoma
ntp authenticate
ntp authentication-key 10 md5 ntpkey
ntp trusted-key 10
ntp server seattle key 10
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
OhioHondo
Sent: Thursday, February 27, 2003 1:05 PM
To: Scott M. Livingston; ccielab@groupstudy.com
Subject: RE: NTP Clarification
Scott
I just got done studying NTP and my experience is the following
NTP master --- Acts as a clock source. I don't believe the NTP process
on a
router that has this set will process received NTP packets.
NTP Client (set with NTP peer) --- Sends unicast requests to another
router's NTP process. I don't believe that it makes a difference how
that
router is configured as long as it has an NTP process and it is
synchronized
to a higher authority. The NTP Client requests NTP packets from other
routers. It processes all received NTP packets favoring the one with the
"prefer" parameter. If the prefer parameter is not set or that peer is
not
available, it favors the response with the highest stratum. (In all
cases
the "peer" providing the NTP packet must be synchronized to be
considered.)
Soooo -- I believe an NTP Client can get NTP packets from another NTP
Client, and NTP Server, an NTP Master, NTP Broadcast Server or an NTP
Broadcast Client.
NTP Server ---- As far as I can tell, used to solicit a clock from an
external clock source. It RECEIVES and processes data from the server
specified in the "ntp server" statement.
NTP Broadcast Server -- Set on an interface connected to a broadcast
media
(ethernet, frame relay, token ring, etc.) -- Sends NTP data out the
broadcast media to 255.255.255.255.
NTP Broadcast Clients -- Set on an Interface, NTP Broadcast Clients
passively listen for NTP packets sent to the 255.255.255.255 destination
address. The do not -- should not -- send out NTP packets.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Scott M. Livingston
Sent: Thursday, February 27, 2003 11:50 AM
To: ccielab@groupstudy.com
Subject: RE: NTP Clarification
Option #2 I meant that if R1 is configured as such it will be able to
receive time not give it to 5.5.5.1. Sorry about that.
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Scott.M.Livingston@mail.sprint.com
Sent: Thursday, February 27, 2003 9:09 AM
To: ccielab@groupstudy.com
Subject: NTP Clarification
I need to get in the lab tonight and nail this down I have only touched
on it. Please correct me if I am wrong. This is what I understand.
A router configured as such:
R1
!
ntp peer 5.5.5.1 <-- Means that R1 can give and receive time from
5.5.5.1.
!
#########
A router configured as such:
R1
!
ntp server 5.5.5.1 <-- Means that R1 can give, but not receive time from
5.5.5.1
!
##########
A router configured as such:
R1
!
ntp master <-- Any router setup with a peer or server statement
pointing to this R1 can get time from it.
!
###########
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