Weird behavior after ISP opens 3 ports

ColombColomb Member Posts: 4

Recently I got T-Mobile’s email asking for an software update for the CellSpot device (signal booster using internet). In the instructions, they require my asking my ISP to open 3 UDP ports: “1) UDP 123: Syncing clocks; 2) UDP 500/4500: VPN or IPSec tunnels, business application. If your ISP confirms the ports are open, ask them to add the CellSpot to a DMZ.” While doing this, my ISP arranged the changes to my iPhone, as they thought it was related to my cell phone. However, the next day I found I was no longer able to connect my iPhone X to one of my Apple TV by AirPlay or screen mirroring. It always shows “connection failure” whatever options I try. Trying to get tech support from Apple has been unsuccessful. Later I realized that this issue might have something to do with above ports opening. I think the changes should be applied to the CellSpot but not my iPhone. But I’m not able to identify it in my home network. Does anyone have the similar experience? Your input and help are sincerely appreciated! Thanks.

Best Answers

  • vulcansheartvulcansheart Posts: 89 ✭✭✭
    edited December 4 Accepted Answer
    If your ISP put your iPhone into a DMZ on your WiFi network, you will not be able to access any other devices on your network. Your ISP needs to reverse that setting (remove the iPhone from the DMZ), and then add the cellspot device to the DMZ. To be clear, no settings were actually applied directly to your phone. Rather, the settings were applied to your router/gateway to place your phone into the DMZ anytime it connects. Therefore, Apple support cannot help you. Only your ISP, or whomever controls your router.
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  • vulcansheartvulcansheart Posts: 89 ✭✭✭
    Accepted Answer
    @Colomb Glad you were able to get it worked out!
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  • ColombColomb Member Posts: 4
    edited December 4

    Thank you so much for the guidance, vulcansheart! Now I know what is the cause. But, in order for my ISP to change the DMZ setting, I need to tell them the name of the CellSpot. The problem is that I am unable to identify which device is it. Will my ISP know it, or I’ll have to provide the name? Is there any way to define the CellSpot? Thanks!

  • vulcansheartvulcansheart Member, Beta Tester Posts: 89 ✭✭✭

    Do you have another device that you can install the fing app onto and scan your network to get the cellspot information?

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  • ColombColomb Member Posts: 4

    Yes. I have a desktop (Windows 10) and a MacBook (also installed Windows 10). How should I proceed?

  • ScoobyScooby Member Posts: 8
    Try looking on the back of the CellSpot, or the box it came in. See if there is a sticker/wording that has something like "MAC: XXXXXXXXXXXX" - you are looking for the CellSpot's MAC address. Your ISP would need that to add it to the DMZ.
  • pwmeekpwmeek Member, Beta Tester Posts: 96 ✭✭✭
    BTW, the MAC address (which may be identified as a serial number) will be 12 characters, each of which will be either a number from 0-9 or letter from A-F (hexadecimal digits); they may be separated into groups of two or four with colons. A typical MAC address looks much like 1a:b2:45:f9:5d:ef or 1ab245f95def
    Since each device needs a unique-in-the-entire-world MAC address, manufacturers rarely bother to create their own serial numbers, but use the MAC address to uniquely number their products.
    Bon Vivant and Raconteur
  • ColombColomb Member Posts: 4

    Hi Scooby and pwmeek,

    Your detailed information is very helpful. This made my call to the ISP much easier. They finally deleted the wrongly opened ports for my iPhone and applied them to the CellSpot. Now I’m able to AirPlay and mirror screen to the Apple TV!

    Thank you so much for the instructions and help. This is an awesome community and I will try to contribute when I am qualified. LOL!

  • CiaranCiaran Administrator Posts: 220 admin
    Brilliant troubleshooting and advise all :smile:
  • vulcansheartvulcansheart Member, Beta Tester Posts: 89 ✭✭✭
    The Windows Fing app is not yet released, so you'll have to choose another network scanning tool if you want to use your laptop or desktop. The most common free tool for Windows is probably Advanced IP Scanner
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