Most fire panels aren’t connected to the internet, only the dialer is. This is for security — hacking into a fire panel would certainly not be ideal, to say the least.
Dialers, whether via software or hardware, are pretty walled off from other panel functionality. However, I believe CLSS has remote time sync capability.
The 4100 panels can also sync with a local Simplex master clock. In addition, networked systems can sync time between nodes, and nodes that are rebooted can pick up their time from others on the network, whether or 4120 or ESNet.