topic Re: Question on NTP setting in Operating System - Linux

Question on NTP setting

Kenneth Leung_2 — Wed, 03 May 2006 20:44:03 GMT

Recently, our IT security man had done a penetration test on the web server runnning RedHat Linux. He asked us to "...set NTP to restrict default access to ignore all info packet by "restrict default ignore"' Can anyone tell me how to set the "restrict..."? Pls help. Thanks a lot.

Re: Question on NTP setting

Warren_9 — Wed, 03 May 2006 21:22:04 GMT

hi,

set the "restrict default ignore" in the /etc/ntp.conf.

GOOD LUCK!

Re: Question on NTP setting

James George_1 — Thu, 04 May 2006 08:39:39 GMT

Hi

check your /etc/ntp.conf file on any system. I thas the examples and will help u to set up this. Here is some examples ..

restrict 129.140.0.0 mask 255.255.0.0 notrust nomodify
#
#Ignore all packets from host 15.1.15.1
#
# restrict 15.1.15.1 ignore
#
# Restric 35.1.1.o to query only
#
#restrict 35.1.1.0 mask 255.255.255.0 noserve nomodify
#
# take time from the 128.116.64.3, but don't let it query
#
#restrict 128.116.64.3 noquery

Rgds / James

Re: Question on NTP setting

Bill Thorsteinson — Fri, 05 May 2006 09:34:22 GMT

Documentation for NTP is at http:/www.ntp.org.
You may have to unrestrict your ntp servers.
Othewise you could loose syncronization.
I believe recent version of NTP automaticaly
accept time from your servers, but older
versions stictly obeyed the restrict commands.

Re: Question on NTP setting

V S Chakravarthi — Fri, 05 May 2006 12:11:23 GMT

http://gentoo-wiki.com/HOWTO_NTP

above link explins how to set it

Re: Question on NTP setting

Florian Heigl (new acc) — Fri, 05 May 2006 12:43:33 GMT

If You want I can dig out a few sample NTP configs for You.

Wow, a security person brought up a real issue and solution.

Invite him on a beer after You implemented it, You're lucky to have someone like him.

:)