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redman |
Posted: Apr 19 2011, 06:17 PM
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![]() Retired SLF Administrator ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Group: Admins Posts: 1276 Member No.: 2 Joined: 8-April 11 ![]() |
Setting up your local time server in your network is simple.
What do you need? One server and one or more workstations. Install the package "ntp" (yum install ntp) on all systems. Open port 123 (both tcp and udp) on the server. On the server, edit the file /etc/ntp.conf and give it the following content:
The settings are relatively simple: 1) only computers connected to the LAN (IP range 192.168.1.x) are allowed access 2) external timeserver may only be queried, they can't change things here 3) your server looks for 3 external timeservers 4) no internet? use the internal clock (as backup) How to start it up? On the server (as root): "service ntpd stop" (to stop the timeserver) "ntpdate -u europe.pool.ntp.org" (used to synchronise your timeserver online - step 1) "ntpdate -u europe.pool.ntp.org" (used to synchronise your timeserver online - step 2) "ntpdate -u europe.pool.ntp.org" (used to synchronise your timeserver online - step 3) "service ntpd start" (start the service again) "chkconfig ntpd on" (make sure it stays on after reboot) On each workstation: Open the application to change system date & time (system-config-date) and select the option that you want to synchronise through the network. Enter the IP address of your local timeserver and you're done. -------------------- "Sometimes the best helping hand you can give is a good, firm push."
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krachbumm |
Posted: Dec 12 2013, 07:38 AM
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SLF Member ![]() ![]() ![]() Group: Members Posts: 66 Member No.: 1961 Joined: 15-October 12 ![]() |
adding some commands that I found useful
http://www.eecis.udel.edu/~mills/ntp/html/ntpdc.html (ntp home) client-side
Find timeservers at http://www.pool.ntp.org |
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krachbumm |
Posted: Apr 26 2014, 04:22 PM
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SLF Member ![]() ![]() ![]() Group: Members Posts: 66 Member No.: 1961 Joined: 15-October 12 ![]() |
SL6.5 still comes with ntp 4.2.6p5. This version can be exploited for a DOS attack (DRDoS_Amplification_Attack_using).
In short, the reply to ntpdc -c monlist is redirected. The default configuration of /etc/ntp.conf is not affected (bugzilla_ntp-4.2.6p5_id1047854). Testing ntp-server; nothing is good here:
The important part of the default configuration /etc/ntp.conf:
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tux99 |
Posted: Apr 26 2014, 06:01 PM
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![]() SLF Moderator ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Group: Moderators Posts: 1278 Member No.: 224 Joined: 28-May 11 ![]() |
I prefer openntpd which is in my Linuxtech repo.
I wrote about it here: http://scientificlinuxforum.org/index.php?showtopic=1401 -------------------- My personal SL6 repository, specialized in audio/video software: http://pkgrepo.linuxtech.net/el6/
(can be used together with EPEL and ELRepo repositories) - repository mirror: http://linuxsoft.cern.ch/linuxtech/el6/ |
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