NTP server

[Asher]

Hello,

How can i make NTP server on my meraki switch MS420 ?

[PhilipDAth · Accepted solution]

No Meraki device can function as an NTP server.

[not_Chuck]

This no longer appears to be the case. I haven't configured anything special but when my phones request NTP from their default gateway, which is a Meraki MX, the MX responds as seen in the following capture.

[PhilipDAth]

Wow that is interesting!  I'll give that a try.

[JohannesM]

I'd open a case with Cisco Meraki to ask for a switch to disable it or to configure. You can't. It's in the DHCP Options. You have to overwrite it with your own DHCP NTP / Time Server Option.

We are establishing our own DHCP Server now, like we did with VPN and IPv6 Router...

Meraki was a mistake.

[MarcelTempelman]

Found this thread after PRTG discovered a SNTP service on a MX. I've tried to configure a MX as a NTP-server on a Catalyst switch..... and it works !

[Uberseehandel]

@Asher

Whilst you can't set up an actual NTP server, there are a couple of DHCP options which may allow you to achieve what you need - 

Option 4 (Time Server)

This option is used to specify the time server available to the client. This is also related to the Time zone offset option.

Option 42 NTP servers

This option carries the NTP servers used on the network.

See - Setting Custom DHCP Options these work for both switches and security appliances.

[PhilipDAth]

The problem with using DHCP is almost nothing uses the NTP options.  I've found some founds that do, but that is about it.

[Uberseehandel]

---

@PhilipDAth wrote:

The problem with using DHCP is almost nothing uses the NTP options.  I've found some founds that do, but that is about it.

---

So far I've only used the ones that do work. For example packet sizes.

[BlakeRichardson]

@Asher is there a real requirement for a local NTP server, can you not rely on an external NTP like time.google.com 

Otherwise does your router not include an NTP option?

[Asher]

@BlakeRichardson

now I have added NTP in the Voice router.

I was in need for NTP to install CUCM.

Thanks,

[King-of-Lag]

retracted

[SteveJones]

@BlakeRichardson I just ran across this --- and stared at this response/inquiry in amazement.   I'm really hoping this was just a joke question, otherwise .........

[KeithR]

Technically you are not supposed to point to outside NTP servers as a matter of Security. It should stay within the Org.
https://www.nwtime.org/news/running-own-ntp-servers/

[annmarie24]

Upstream Firewall Rules for NTP

Meraki devices must be able to resolve pool.ntp.org and reach it via UDP port 123: