Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

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Anthony's avatar
Anthony
Icon for Nimbostratus rankNimbostratus
Feb 19, 2014

NTP not sync'ing - what interface is used?

Hi all, I'm currently going through a complete reconfigure of our internal loadbalancers and at the moment wI'm stuck on getting NTP working. Configuring of the internal/external/HA VLANs and a...
Anthony's avatar
Anthony
Icon for Nimbostratus rankNimbostratus
Feb 19, 2014

Using the IP address it returns the exact same output as using the DNS entry.

I think I got the entry right:

[root@LB1:Active:In Sync] config  tcpdump -s0 -i 0.0 host ntppub.le.ac.uk &
[1] 19900
[root@LB1:Active:In Sync] config  tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on 0.0, link-type EN10MB (Ethernet), capture size 65535 bytes

[root@LB1:Active:In Sync] config  ntpdate ntppub.le.ac.uk
17:12:15.127766 IP 192.168.74.1.ntp > ntppub.le.ac.uk.ntp: NTPv4, Client, length 48 out slot1/tmm0 lis=
17:12:16.127683 IP 192.168.74.1.ntp > ntppub.le.ac.uk.ntp: NTPv4, Client, length 48 out slot1/tmm0 lis=
17:12:17.127722 IP 192.168.74.1.ntp > ntppub.le.ac.uk.ntp: NTPv4, Client, length 48 out slot1/tmm0 lis=
17:12:18.127730 IP 192.168.74.1.ntp > ntppub.le.ac.uk.ntp: NTPv4, Client, length 48 out slot1/tmm0 lis=
19 Feb 17:12:19 ntpdate[19913]: no server suitable for synchronization found

Using the IP address of the NTP server again yields the same results.