Does Any Radio Really Know What Time It is?
TL;DR Today I learned that some SiriusXM devices are serious about their NTP servers.
Help Desk let me know that one of our vendors was having an issue getting a radio set up at one of our provider locations and needed a hand. I used to work for this particular vendor and the guy needing help was a former colleague (henceforth VendorGuy) so I was more than happy to help.
I called VendorGuy up, found out that the device in question was a Grace Digital SiriusXM SXBR3 and then proceeded to battle with the fact that the device was physically connected to the network switch, showed the proper network info acquired via DHCP, and was pingable yet still stubbornly insisted that it had no network connection. This did appear to be true as our firewall logs showed no dropped traffic originating from the device's IP.
I had a hunch we might be missing something so I hopped on our firewall's CLI and ran a tcpdump filtering for the player's IP address and had VendorGuy reboot the device. Sure enough, I saw traffic, NTP traffic, to be precise. Which we block by default and do not log, so that explained why I didn't see the traffic. Apparently SiriusXM devices (these ones, at least) give up trying if they can't establish connections to pre-programmed NTP servers. Once we allowed that device's NTP requests out, then rebooted it to force reconnection, we were in business.
VendorGuy got the device hooked up to its amp and the PA system, there was music again and subsequent rejoicing. VendorGuy and I exchanged pleasantries and went our separate ways until the next issue comes to bear.