Problem With Ntp

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Hi all,

I have a problem with ntpd daemon in my CentOS7 vm. When I try to list peers, command fails:

[root@c7tst ntpstats]# ntpq ntpq> pe ntpq: read: Connection refused ntpq>

My actual ntp.conf:

# For more information about this file, see the man pages
# ntp.conf(5), ntp_acc(5), ntp_auth(5), ntp_clock(5), ntp_misc(5), ntp_mon(5).

driftfile /var/lib/ntp/drift

# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system. restrict default nomodify notrap nopeer noquery

# Permit all access over the loopback interface. This could
# be tightened as well, but to do so would effect some of
# the administrative functions. restrict 127.0.0.1
#restrict ::1

# Hosts on local network are less restricted.
#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html). server 0.europe.pool.ntp.org iburst server 1.europe.pool.ntp.org iburst server 2.europe.pool.ntp.org iburst server 3.europe.pool.ntp.org iburst

#broadcast 192.168.1.255 autokey # broadcast server
#broadcastclient # broadcast client
#broadcast 224.0.1.1 autokey # multicast server
#multicastclient 224.0.1.1 # multicast client
#manycastserver 239.255.254.254 # manycast server
#manycastclient 239.255.254.254 autokey # manycast client

# Enable public key cryptography.
#crypto

includefile /etc/ntp/crypto/pw

# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography. keys /etc/ntp/keys

# Specify the key identifiers which are trusted.
#trustedkey 4 8 42

# Specify the key identifier to use with the ntpdc utility.
#requestkey 8

# Specify the key identifier to use with the ntpq utility.
#controlkey 8

# Enable writing of statistics records. statistics clockstats cryptostats loopstats peerstats

# Disable the monitoring facility to prevent amplification attacks using ntpdc
# monlist command when default restrict does not include the noquery flag. See
# CVE-2013-5211 for more details.
# Note: Monitoring will not be disabled with the limited restriction flag.
#disable monitor

I have tried to disable all “restrict” statements without luck. Same ntp.conf works in my CentOS6.x hosts …

Any idea why?? (SELinux is disabled)

Thanks.

3 thoughts on - Problem With Ntp

  • Hi,

    By default NTP daemon is stopped in CentOS. Please see NTP daemon is running or not?

    Please share the output of “netstat -nupl | grep 123” command for more information.

    –Regards Ashishkumar S. Yadav

  • Hi Ashish,

    of course, ntpd daemon is running:

    [root@c7tst tmp]$ ps xauw | grep ntp ntp 8238 0.0 0.0 29360 2076 ? Ss 11:09 0:00
    /usr/sbin/ntpd -u ntp:ntp -g -4

    And:

    [root@c7tst tmp]$ sudo ss -putan | grep 123
    tcp UNCONN 0 0 172.22.55.1:123
    *:* users:((“ntpd”,8238,18))
    tcp UNCONN 0 0 127.0.0.1:123
    *:* users:((“ntpd”,8238,17))
    tcp UNCONN 0 0 *:123
    *:* users:((“ntpd”,8238,16))

    And /var/log/messages:

    Mar 9 09:31:04 c7tst ntpd[6030]: proto: precision = 0.055 usec Mar 9 09:31:04 c7tst ntpd[6030]: 0.0.0.0 c01d 0d kern kernel time sync enabled Mar 9 09:31:04 c7tst ntpd[6030]: Listen and drop on 0 v4wildcard
    0.0.0.0 UDP 123
    Mar 9 09:31:04 c7tst ntpd[6030]: Listen normally on 1 lo 127.0.0.1 UDP 123
    Mar 9 09:31:04 c7tst ntpd[6030]: Listen normally on 2 prodif
    172.22.55.1 UDP 123
    Mar 9 09:31:04 c7tst ntpd[6030]: Listening on routing socket on fd #19
    for interface updates Mar 9 09:31:04 c7tst ntpd[6030]: 0.0.0.0 c016 06 restart Mar 9 09:31:04 c7tst ntpd[6030]: 0.0.0.0 c012 02 freq_set kernel -2.019 PPM
    Mar 9 09:31:05 c7tst ntpd[6030]: 0.0.0.0 c615 05 clock_sync Mar 9 11:09:05 c7tst ntpd[6030]: ntpd exiting on signal 15
    Mar 9 11:09:09 c7tst ntpd[8237]: ntpd 4.2.6p5@1.2349-o Sat Dec 20
    01:24:55 UTC 2014 (1)
    Mar 9 11:09:09 c7tst ntpd[8238]: proto: precision = 0.066 usec Mar 9 11:09:09 c7tst ntpd[8238]: 0.0.0.0 c01d 0d kern kernel time sync enabled Mar 9 11:09:09 c7tst ntpd[8238]: Listen and drop on 0 v4wildcard
    0.0.0.0 UDP 123
    Mar 9 11:09:09 c7tst ntpd[8238]: Listen normally on 1 lo 127.0.0.1 UDP 123
    Mar 9 11:09:09 c7tst ntpd[8238]: Listen normally on 2 prodif
    172.22.55.1 UDP 123
    Mar 9 11:09:09 c7tst ntpd[8238]: Listening on routing socket on fd #19
    for interface updates Mar 9 11:09:10 c7tst ntpd[8238]: 0.0.0.0 c016 06 restart Mar 9 11:09:10 c7tst ntpd[8238]: 0.0.0.0 c012 02 freq_set kernel -1.971 PPM
    Mar 9 11:09:10 c7tst ntpd[8238]: 0.0.0.0 c615 05 clock_sync

    But, I am worried about two things. First in /var/log/messages:

    Mar 9 11:09:09 c7tst ntpd[8238]: Listen and drop on 0 v4wildcard
    0.0.0.0 UDP 123

  • Yep, using “ntpq -4”, works:

    [root@c7tst tmp]$ ntpq -4
    ntpq> pe
    remote refid st t when poll reach delay offset
    jitter
    =============================================================================*lafkor.de 192.93.2.20 2 u 5 64 1 64.748 1.130
    0.268
    primary.server. 134.130.5.17 2 u 4 64 1 83.842 1.120
    0.614
    ntp1.warwicknet 195.66.241.10 2 u 5 64 1 66.697 -1.593
    0.504
    ntp.univ-poitie 193.50.27.66 3 u 5 64 1 72.149 10.225
    2.323
    ntpq> quit

    Uhmm .. Then, my problem is with Ipv6. I have disabled all IPv6 stack using ipv6_disable=1 in grub.cfg …

    According to this I need to re-enable … Correct??