$ttl entry obsolet in DNS records ?!

[suther]

SYSTEM INFORMATION
OS type and version	Ubuntu Linux 20.04.6
Webmin version	2.021
Usermin version	1.861
Virtualmin version	7.5
Theme version	20.21
Package updates	All installed packages are up to date

Today I found that in DNS records is a Variable $ttl, that isn’t used anywhere in the DNS-Records.
I wonder if that variable is obsolete?

Shouldn’t it be placed in front of SOA by default:

$ttl 3600
@	$ttl  IN	SOA	abc.com. root.abc.com. (
			1679942683
			3600
			900
			1209600
			3600 )

I’ve checked that on different servers, and nowhere I’d found a usage of this $ttl Variable.
Or is sit only some kind of setting for the DNS, which set TTL automatically in background for the Zone where $ttl 3600 is added?

[suther]

BTW: If I do change DNS-Record via `Virtualmin → → Server Configuration → DNS Records, the NS seems not to be reloaded…, right?!

I’ve worked on some DNS entries today and found that I need to go to Webmin → Servers → Bind DNS Server and hit the “Aply Configuration” Button.

Would be nice if DNS would apply changes automatically if something is changed in Virtualmin DNS Records… or at least to have such an button to reload it manually (even if only as Admin-User).

[Lukinno]

Hello,

according to 3. Configurations and Zone Files — BIND 9 9.18.13 documentation this variable is “default TTL for zone”

I think that this is default TTL value for all records, where is TTL not configured