We only block TCP & UDP ports 135-139 – Used by NetBIOS.
The ports present a potential security risk to customers
Are you shure that port 113 isn't blocked as well ?
Just did a port scan on Shields Up and as well as 135 to 139 being blocked, port 113 is as well. Using a Fritzbox 3490 in router only mode with a Vigor 130 as the modem and a Netgear Orbi for the Wifi.