Here is an express “how to” guide to configure SNTP on Extreme Networks switches (X440-G2 and X435 in my case).
SNTP service is used to synchronize time over network thanks to a protocol called NTP.
First thing first, if you have any firewall, please be sure to open following access for traffic from switches :
- NTP request to 0.fr.pool.ntp.org (and 1.fr.pool.ntp.org)
- DNS request to desired DNS server
Before going further, you’ll need to configure DNS on your switches in order to resolve NTP server address :
switch# configure dns-client add name-server 22.214.171.124 vr VR-Default
Please note : bold elements in the previous can be changed as you wish and may differ according to your own configuration. You can also add a secondary DNS server.
Configure time zone
Then, you’ll need to configure time zone :
switch# configure timezone name UTC 120
Please note : bold elements can be changed. In my case, I’ve set it up for my own use with French time zone.
- UTC means the name of the zone (standard) you can also use CET (which is 1 hour ahead UTC) or GMT…
- 120 is the gap (in minutes) from the standard you’ve chosen (UTC +2h in that case, but in minutes…)
Configure SNTP client
Now, let’s configure SNTP client :
switch# configure sntp-client primary 0.fr.pool.ntp.org vr VR-Default
As previous commands : bold elements may vary for your own configuration.
Enable SNTP client
After this short configuration, you’ll need to enable SNTP configuration :
switch# enable sntp-client
Check you configuration
You can check the good configuration of SNTP client by using this command :
switch# show sntp-client SNTP client is enabled SNTP time is valid Primary server:fr.pool.ntp.org VR-Default Secondary server: Broadcasts: VR-Mamt Query interval:64 Last valid SNTP update: From server:0.fr.pool.ntp.org, on Mon May 9 10:26:27 2022 SNTPC Statistics : Packets transmitted: to primary server: 18 to secondary server: 0 Packets received with valid time: from Primary server: 5 from Secondary server: 0 from Broadcast server: 0 Packets received without valid time: from Primary server: 0 from Secondary server: 0 from Broadcast server: 0 Replies not received to requests: from Primary server: 13 from Secondary server: 0
In order to validate SNTP configuration, you’ll need to check following elements (in bold) :
- SNTP client is enabled
- SNTP time is valid
- Primary server
- Packets received with valid time
Please note that in my case, I got few packets categorized as “Replies not received to requests” which corresponds to a period where SNTP was trying to get response (beginning of sync).
You can also configure a “secondary server” with the following command :
switch# configure sntp-client secondary 1.fr.pool.ntp.org vr VR-Default
Here is a short recap (for admins who don’t have time) :
switch# configure dns-client add name-server 126.96.36.199 vr VR-Default switch# configure timezone name UTC 120 switch# configure sntp-client primary 0.fr.pool.ntp.org vr VR-Default switch# configure sntp-client secondary 1.fr.pool.ntp.org vr VR-Default switch# enable sntp-client switch# show sntp-client
Finally, this command may return the correct date and time :
switch# show time
Hope you’ll enjoyed this brief article, thanks for reading !