Once you connect to a communications network (i.e.; the customer's network) it's no longer part of the fire alarm and fire listing is not required; just like connecting a digital communicator to a POTS line, the listing required from the demarc and "out" is for communication networks. That said, I always stressed all switches, routers and firewalls should have minimum 24 hour stand-by power (UPS), explained why and played the "your insurer might refuse to pay" card if there is no stand-by power. My proposal to do Internet monitoring included necessary UPS(s), installation and testing (customer had the option to decline the UPS, but a signature was required to decline).
The IT people sometimes didn't like the idea, see the need for it, want anyone near their equipment or look kindly at another reason to stay late to repower their equipment after UPS installation. (You usually don't want to take a network down during normal working hours.) I added the UPS to my Inspection/Testing agreement, usually at a premium since killing AC power to a network UPS will probably be done outside normal working hours. I also included UPS batteries in the 4-year battery replacement schedule.
IT will give you a static address and subnet mask for the panel and
SHOULD block that address from being assigned by their DHCP server;
be sure to request they do so. For various reasons networks get reconfigured (IP ranges, subnets, segmentation, port blocking, etc) and this can cause communication problems (what IT doesn't control usually gets forgotten). Asking about recent network changes was on my troubleshooting list, but not at the top (a good relationship with IT can save you a lot of grief
) even if maybe it should have been.
If your are not into networking, cell communicators may be a better option. Specifics will be determined by the technology (CDMA and GSM are the most common) of the carrier you choose.
Keep in mind I've been retired several years and requirements change. I still help out when needed (part of every week for a while now) and next week I'll talk to people who do Internet monitoring every day, see how they handle it, see if I missed anything and post again.
Regards!