Most AT&T U-Verse subscribers receive a 2wire residential gateway for their subscription to Internet, TV, and VoIP phone service. I believe most subscribers get a 3800HGV-B. The user guide for that model does not mention anything about a TCP Port 3479 being opened or used by default. So I found it strange to see TCP port 3479 open when I performed a full TCP port scan from the Internet to my external U-Verse IP:

nmap -sSV -n -P0 -p- “ip”

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