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I have a problem where when i restart bind or reboot the physical machine (local dev server) then my router goes through a power cycle taking the whole network down. Plusnet hub one AKA BT Hub 5.

I could not figure it out for quite some time so got help from ISPConfig as it was always when i altered dns from the control panel. They explained that the only thing that occurs is an update of files and a restart of bind.

Sure enough when i restarted bind manually I immediately triggered the power cycle, i should have seen it before as it happened when i triggered reboot too, whether at the server or over the network.

So: I spoke to people on the bind mailing list and they state that nothing really happens when the bind service is restarted that should cause this issue. They did say that a call goes out to the ISP for information from the glue records and it could be that which is triggering the power cycle.

Now i am in the situation where i have a fair idea of what is causing the issue but no clue as to how i would test it out to be sure.

I just found out how to trigger the DNS call out, which cycled my router:

dig +trace @a.root-servers.net ns0.my-domain-here.com

So the question i have: How can i make/spoof a dns response to my server without making the call out as if its from the root-server to find out if its the response causing it (this was the primary suspect that arose from the conversation).

I hope that somebody can help me out, i know dns rarely changed but when it does have to be changed then i lose my network for a time.

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    Cripes, just replace your busted router.
    – EEAA
    Jun 3, 2017 at 0:47
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    I think it's more of a router problem, and since it's not a very commonly-used router, you probably won't get an answer here. I would open a support case with the vendor, or do what @EEAA said... replace it. If the main problem is that it can't query a root DNS server, just set it to use forwarders, and don't forget the "forward only" statement to keep it from ever querying a root.
    – theglossy1
    Jun 3, 2017 at 1:07
  • Actually its very common, the hub one (plusnet) is a rebranded BT home hub 5a. so its well used and has been supplied for some time by BT, they have since stopped supplying it and moved onto the hub 6 last i checked, maybe moved on again by now. The hub one/5a is a new supply from plusnet, in the last 12-15 months i believe since they switched to it. ive been reading up on using OpenWRT on this very same router so I will throw my old slower router onto the line and flash this one, for half an hours tinkering it might solve the problem. nothing ventured and all that. Thanks for the comments. Jun 3, 2017 at 1:18
  • I suppose the easiest and more likely the best option would be to stop being so cheap, set up external dns servers and remove bind. That would solve the call out to the root servers too. Jun 3, 2017 at 1:22
  • Provide the true domain name involved without obfuscation. There may be an invalid DNS configuration somewhere. Which, if it exists, must be fixed but in no way should it make a router misbehave, so I agree with @EEAA you should just ditch it, trying to spoof DNS response will cause you more harm than anything good. Jun 3, 2017 at 11:00

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