Solved

Help with NTP on a new Cisco 3850 switch

Posted on 2014-10-27
7
1,917 Views
Last Modified: 2014-11-04
Hello All,
Hello All,

We put in a new Cisco 3850 this last weekend.  The switch is working fine except for NTP.  The new switch is supposed to be the NTP server for the network.  However, other switches and servers are not syncing with the new switch, and I'm not seeing what the issue is.  The new switch is syncing with the atomic clock fine.  Below is the configuration for NTP on the new switch.


SW3850#show run | i ntp
ntp source Vlan2
ntp access-group peer 10
ntp access-group serve-only 20
ntp master
ntp server 192.43.244.18 source Vlan2
ntp server 132.163.4.101 prefer source Vlan2
ntp server 132.163.4.102 source Vlan2
ntp server 132.163.4.103 source Vlan2


Regards,
Nick Dalmolin
0
Comment
Question by:ndalmolin_13
  • 4
  • 2
7 Comments
 
LVL 45

Expert Comment

by:Craig Beck
ID: 40407922
Can you post ACL 10 and 20 too please?
0
 
LVL 12

Accepted Solution

by:
Fidelius earned 500 total points
ID: 40407927
Hello,

Remove command ntp master. By default, if this switch is configured with the external NTP server, it will act as NTP Master for the rest of devices in your network which point to it as NTP server.

Here is explanation of command:
http://www.cisco.com/c/en/us/td/docs/ios/12_2/configfun/command/reference/ffun_r/frf012.html#wp1123474

Regards!

Fidelius
0
 
LVL 45

Expert Comment

by:Craig Beck
ID: 40408484
Fidelius is right, but that wont 'stop' clients connecting to the switch as a ntp client.  It just forces the switch to give the time to clients from its own hardware clock.
0
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

 
LVL 12

Expert Comment

by:Fidelius
ID: 40409356
I agree. But ntp master command sometimes makes trouble. As it is not needed in this case, it is better to remove it, before further troubleshoot
0
 
LVL 45

Expert Comment

by:Craig Beck
ID: 40409413
The only trouble I've ever had with ntp master is when you have more than one in your network.  This can cause stratum issues and loss of sync.  I do agree though, it's not required - I was just mentioning that it won't stop devices from syncing as clients.
0
 
LVL 1

Author Closing Comment

by:ndalmolin_13
ID: 40421700
Thanks all for the help.  Apologies for not getting back to this sooner.  I was out of the office last week.
0
 
LVL 45

Expert Comment

by:Craig Beck
ID: 40421850
So did the chosen answer work?
0

Featured Post

Easy, flexible multimedia distribution & control

Coming soon!  Ideal for large-scale A/V applications, ATEN's VM3200 Modular Matrix Switch is an all-in-one solution that simplifies video wall integration. Easily customize display layouts to see what you want, how you want it in 4k.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

The worst thing when starting a new job is when the previous Network Administrator left behind no documentation. How do you get into the devices? If you've been in this situation or just accidently mistyped your password, this article will hopefully…
I eventually solved a perplexing problem setting up telnet for a new switch.  I installed a new Cisco WS-03560X-24P switch connected to an existing Cisco 4506 running a WS-X4013-10GE Sup II-Plus. After configuring vlans and trunking,  I could no…
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question