What is "External IP:Port"? Why are my mesh APs isolated?

[kurt_todoroff]

Issue:
I have 3 ZF7962s, all on the same LAN/Subnet, running IPv4.
All 3 ZF7962s are controlled by a ZoneDirector 1106 running 9.7.1.0 Build 17.
I run them in mesh configuration. The ZD connects to the network switch. ZF1 connects to the ZD. ZF2 and ZF3 are located at other locations in my building.
I use the ZD and ZFs in my office for testing, learning, demonstration, and for Wi-Fi site surveys at prospective clients’ locations.
Until recently, all 3 APs had a blank External IP:Port.
Within the last two weeks, all 3 of them began to display an External IP:Port of :12223.
Today, all 3 APs are displaying an External IP:Port of :12223.
The connection mode is L3 (IPv4) on all 3 APs. I am not certain why this is.
Furthermore, the two mesh APs became isolated. Now, they are disconnected.

History:
This is a 100% layer 2 environment, that has been online for two years.
This problem first appeared two weeks ago.
At that time, I switched from AT&T U-Verse DSL to Comcast cable for our Internet connection.
The DSL modem IP address was 192.168.1.254.
The cable modem IP address is 10.1.10.1.
I has set static IP addresses in the ZD of 192.168.1.111 (ZD) and 192.168.1.112, .113, .114 (3 ZFs).
After I switched to Comcast cable, I could not access the ZD.
The WLANs that I had created in the ZD, still appeared on our iPhones and laptops, and, these devices could still connect to them.
I connected the ZD to the AT&T DSL router. I accessed the ZD, and, I disabled the static IP addresses
I connected the ZD to the Comcast gateway. I accessed the ZD, and, I saw that the Comcast gateway had assigned 10.1.10.17 to the ZD, and 10.1.10.18, .19, .20 to the three ZFs. This is when the problems started to occur.

Questions:
What does the External IP:Port tell me?
How can I resolve these issues (External IP:Port, mesh isolation/disconnect), and, return my system to proper working order?
Once I resolve these problems, should I, or, should I not configure the four devices with static IP addresses?