Or, as the French would say, "Bonjour".
My firewall was reporting a whole bunch of UDP accesses from 10.149.14.189/52908 to 192.168.1.100/57378, and it was, of course, blocking them. But I wondered what this was all about, and decided to investigate.
10.149.14.189 is a non-routable (private) IP address, because it starts with 10. The "149.14" means that it's an address got via DHCP from my main DHCP server. In other words, it's a device based on my DMZ that picks up its IP address from another of my servers.
The 192.168.1.100 is a mystery. My "innermost" network starts with 192.168, which is also a private, non-routable address, but I don't have a device at that address. Furthermore, why would a device on my DMZ go looking for a device at that address?
So I googled.
Googling doesn't always produce the answer straight away. The first stop was https://tech.lds.org/forum, which is a technical forum ... with a difference. I read halfway down the article that Google found, then burst into giggles. "lds" = "Latter Day Saints" = Mormons.
"No other software should be purchased or installed on Church computers
unless it is approved by the stake president, is appropriately licensed,
and does not interfere with the operation of or compromise the security of the Church software and data already on the computer." which is fair enough. :
And then " Other then it needs to be password protected and not uploaded to 3rd
party servers, no. However, I would involve the Bishop in who is
getting the information and what the information contains."
Can you imagine what it must be like for those tech support staff, having to get a Bishop involved when they have a support issue? What does the Bishop do, pray for guidance? Yes, I can see that even a church needs appropriate computer security; I'd guess that many churches use computers to do their accounts and suchlike. But involving the Bishop?
So after getting past this distraction, I found some useful information. I think it has to do with Apple's Bonjour, which is how Apple devices find other things on the network, and the device doing the looking was indeed ladysolly's iPhone.
Rather mundane and uninteresting, but I would never have found the LDS tech web site without it, and discovered the role of LDS Bishops in their tech support.