I have a Texecom 412 with v10.4 and ComIP.
I setup the ComIP and can ping it, AND connect to it using Wintex over my LAN.
Additionally, I port-forwarded ports on my router so I can also see the ComIP over the Internet.
To test, I reset my UDL to 1234. I configure Wintex with UDL of 1234 over...