MT-6000 - Flint 2 - Sky FTTP problem with MAP-T

Router
1

Anyone else having IPv4 problems with their MT-6000 - Flint 2 (firmware 4.11.1 beta) and Sky FTTP which I think are due to their MAP-T system.

Router randomly keeps acquiring new "public" IPv4 address in the 100.x.x.x range which I think is a sign of MAP-T (like CGNAT) as work and I loose all IPv4 access, i.e. clients that can't do IPv6 can no longer access the internet. Mostly a single router reboot persuades it to claim a 94.x.x.x or 90.x.x.x etc IP and IPv4 access is restored.

2

I also have this issue when Sky renews my public facing IP roughly every 56 days and if I am not around the Flint2 router will fail to re-negotiate a new IP and stay in the 100.x.x.x range. I think it is rubbish that Sky operate behind both CG-NAT & MAP-T protocols and unless we can find a fix I will be leaving to an ISP that doesn't use these silly systems, such as BT or Plusnet.

I have also come across a potential work-around but I've not tested it yet and wanted to post it here for someone at GL-iNET to confirm this is the best work-around for us?

Automatically Renew via a Cron Watchdog Script

To prevent this issue from happening when you aren't around, you can create a lightweight watchdog script on the Flint 2 that tests for internet connectivity and auto-renews the WAN connection if the connection drops after an IP change.

  1. SSH into your Flint 2.

  2. Create a script file in an appropriate persistent directory:

    bash

    vi /etc/config/wan_watchdog.sh

    Use code with caution.

  3. Paste the following automated script (press i to enter insert mode in vi):

    bash

    #!/bin/sh
# Ping a stable public DNS server to test connectivity
if ! ping -c 2 -W 3 8.8.8.8 > /dev/null 2>&1; then
    logger "WAN Watchdog: Internet disconnected (possible IP change). Forcing WAN renew..."
    ifup wan
fi

    Use code with caution.

  4. Save and exit (press ESC, then type :wq and hit Enter).

  5. Make the script executable:

    bash

    chmod +x /etc/config/wan_watchdog.sh

    Use code with caution.

  6. Add it to the system router scheduler (Cron) so it runs every 2 to 5 minutes:

    bash

    echo "*/2 * * * * /etc/config/wan_watchdog.sh" >> /etc/crontabs/root

    Use code with caution.

  7. Enable and restart the cron daemon to register the task: [1]

    bash

    /etc/init.d/cron enable
/etc/init.d/cron restart