Virgin Media Hub 4 in modem mode and DrayTek Router. Frequent reboot.
Good afternoon All,
After spending a horrible weekend trying to troubleshoot a sporadic reboot of my DrayTek router, sitting behind a VM Hub 4 in modem mode, decided to share something, which might help others in the same situation.
In short the setup is: Virgin Media Hub 4 in modem mode serving as a gateway for a DrayTek router handling all home routing and services.
Exhibit of the problem: eratic and unexplained reboot of the DrayTek router every 5 - 10 minutes since Saturday 22nd of March 2025
After spending hours of trying to troubleshoot the issue by checking every single node on my network and disabling individual segments, applying various of severe firewall rules etc, I concluded that the problem is due to the DrayTek router being connected to VM Hub 4 sitting in modem mode. This way the DrayTek router is directly exposed to the internet.
Having a long conversation with the VM Support team, didn't bring much joy or solution.
I ended up switching off completely the DrayTek and quickly setting up the VM Hub 4 in router mode and leaving it like that.
This seems to have resolved the problem with the reboot naturally as DrayTek is off the game. However, it kept me uneasy, why after 4 months of perfectly working, this issue appeared out of the blue. Is it the DrayTek, is it the VM Hub 4 or is there anything else. I have had no changes implemented in my network for months, therefore I excluded the possibility of a configuration to be leading to this.
I was confused untill an hour ago, when I came across an article announcing a probable attack on DrayTek routers around the world:
https://www.ispreview.co.uk/index.php/2025/03/broadband-isps-report-uk-connectivity-problems-with-vulnerable-draytek-routers.html
This explained it all! There seems to be a vulnerability in the DrayTek routers that has been exploited and it is not just in UK but worldwide.
Therefore, if you are experiencing any strange outages of the service, reboots of your router or other suspicious behaviour of your router, especially if it is DrayTek and sitting behind VM Hub in modem mode, before ringing VM support, check the above article and try to neutralise this vulnerability.
I am currently in the process of trying to patch the DrayTek router and see if that would resolve it for me. Needless to say that DrayTek's website is currently experiencing issues, perhaps due to volume of requests, but be patient and try to implement whatever you can from the suggestions in the article.
Best Regards
Ian
