OpenWrt: NTP Server Configuration

NTPD USAGE

root@OpenWrt-2:/# ntpd
BusyBox v1.19.4 (2013-03-06 20:07:44 UTC) multi-call binary.

Usage: ntpd [-dnqNwl] [-S PROG] [-p PEER]…

NTP client/server

-d      Verbose
-n      Do not daemonize
-q      Quit after clock is set
-N      Run at high priority
-w      Do not set time (only query peers), implies -n
-l      Run as server on port 123
-S PROG Run PROG after stepping time, stratum change, and every 11 mins
-p PEER Obtain time from PEER (may be repeated)

root@OpenWrt-2:/#

### NTP SERVER CONFIGURATION ###

START NTP SERVICE

root@OpenWrt-2:/# ntpd -l
root@OpenWrt-2:/#

VERIFY NTP SERVICE (UDP/123) IS UP AND RUNNING

root@OpenWrt-2:/# ps | grep ntpd
1422 root      1248 S    /usr/sbin/ntpd -n -p 0.openwrt.pool.ntp.org -p 1.ope
7613 root      1240 S    ntpd -l
7642 root      1240 S    grep ntpd

root@OpenWrt-2:/#

root@OpenWrt-2:/# nmap localhost -sU

Starting Nmap 6.01 ( http://nmap.org ) at 2013-09-06 12:08 UTC
Nmap scan report for localhost (127.0.0.1)
Host is up (0.0000070s latency).
Not shown: 998 closed ports
PORT    STATE SERVICE
53/udp  open  domain
123/udp open  ntp

Nmap done: 1 IP address (1 host up) scanned in 0.05 seconds
root@OpenWrt-2:/#

### NTP CLIENT CONFIGURATION ###

1. Download ntpdate

opkg update && opkg install ntpdate

TO VERIFY CLIENT/SERVER CONFIGURATION

1. Change date on the client side

root@OpenWrt1:~# date 20:00
Fri Sep  6 20:00:00 UTC 2013
root@OpenWrt1:~#

2. Compare date with the server

root@OpenWrt-2:/# date
Fri Sep  6 12:18:19 UTC 2013
root@OpenWrt-2:/#

3. Run ntpdate to get new time from the server

root@OpenWrt1:~# ntpdate 192.168.10.12
6 Sep 12:18:12 ntpdate[11630]: step time server 192.168.10.12 offset -27726.790601 sec
root@OpenWrt1:~#

4. Verify both date in client & server

root@OpenWrt1:~# date
Fri Sep  6 12:22:04 UTC 2013
root@OpenWrt1:~#

root@OpenWrt-2:/# date
Fri Sep  6 12:22:04 UTC 2013
root@OpenWrt-2:/#

PERFECT!!!

REFERENCE

http://wiki.openwrt.org/doc/howto/ntp.client

https://dev.openwrt.org/ticket/10448