Ntp synchronisation on ds2824

I can’t find an option on ds2824 config to set a ntp server address.
The board is trying to get connection to sites like time cloudflare and others on port 123.
But I’m working in an internal net which is blocked by a firewall from getting contact to the internet.
Did I not see the option or is there no option or can I set a timeserver address with DScript?
Thanks for your help.
Ruediger Stamm