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DNS Name Resolution Failure

Message 7 of 7


I posted earlier about my WiFi mesh problems, but a little more investigation is making me think it is actually the router which is causing problems.  


On the maintenance logs from the router I have pages and pages of DNS Name Resolution Failures.  From looking at other posts, it seems these are linked to the connected by no internet message that I have been encountering recently.  This is causing quite significant issues for me when working at home when my work connection suddenly drops with no warning.


I think my router is the Sagemcom Wifi Hub Black and is currently on firmware version SG4K10002816t.  Not sure if this is relevant or not to this problem.  


Please can someone help or advise if I need to be doing something different.





Message 1 of 7

Hi Matt


I can see that @Skynet_TX has helped with this.


Please let us know how the connection compares.


Thanks @Skynet_TX

Community Star
Message 2 of 7

Thanks, my Sagemcom had these same problems, I applied this tweak about 6 months ago, and it resolved the issues for me. However if you still have problems then just post back here to let us know, the staff here will then be able to pick this up next week to assist.

Message 3 of 7

Hi @Skynet_TX 


Thanks for this.  I'll give it a whirl now and see how I get on!  Have a good evening (what's left of it anyway ;-)).



Community Star
Message 4 of 7

Ok, details are below, it is easy to undo the change if it doesn't fix it, or causes any issues with your setup. Note that you have the 'Wi-Fi Hub', NOT the 'Wi-Fi Hub Black' (The 'Black' is the Huawei model, you have the Sagemcom model) :


At present your router will be acting as the DNS server for all of your devices, so when the DNS stops working in your router all of your devices will lose internet access. However you could configure your router so that it just tells all of your devices to use the TalkTalk (or any other providers) DNS servers directly, therefore your devices won't use the router as a DNS server, and so shouldn’t be affected if the routers DNS stops working.


If you wanted to try this you just need to follow the instructions for the 'Wi-Fi Hub' here (ensure you go to the screen described in this article, as there are two screens in the router where you can modify DNS settings, but you must change the settings on the specific screen described in this article for this potential fix to work). If it won't let you change the settings in this screen it may be because you have set specific DNS servers in the other screen where you can modify the DNS settings, if this is the case then go back and set that other screen back to Auto, that should then allow you to edit the details on this screen.


If you have never changed these settings before you will probably find that the primary DNS server is set to (i.e. the router itself). You could change the settings as follows (or use any other DNS service of your choice) :


Primary :
Secondary :


These are the current preferred TalkTalk DNS servers (they are mentioned at the bottom of that webpage so you know they really are genuine TalkTalk DNS servers).


IMPORTANT : Having changed the settings you would need to make your devices disconnect and reconnect to the router (you could just reboot the devices or the router). When your devices have reconnected they will be configured to use those two addresses above as their DNS servers. So from that point on the devices will use those DNS servers directly rather than going via the routers DNS service.


Making this change may well resolve the issues for you, but if you do ever want to 'undo' this change all you need to do is put the old values back into that screen, or you could just factory reset the router by holding in the pinhole reset switch on the back for over 10 seconds, but that will return all settings back to their initial defaults.

Message 5 of 7

Hi - thanks for such a quick reply.  I'm happy to give your fix a go to see if that sorts the problem.  I don't think I have devices which need to see each other but if anything falls over I can back this out!



Community Star
Message 6 of 7

Hi @tamtb78,


There is a known issue with firmware SG4K10002816t that can cause DNS resolution to fail, this means the LED remains solid white, but your devices effectively lose internet access, a reboot will get things working again, but the problem will then happen again after some time.


There is a new version of firmware that is being rolled out at the moment that resolves this issue, but the rollout is quite slow due to some other issues that are being investigated with it.


In the short term the staff here may be able to offer you a replacement router of a different type (the Huawei Hub), this is not affected by the DNS issue and so would stop you from having this specific problem.


Alternatively, if you are comfortable with logging into the Sagemcom router and changing a setting then you may well be able to stop the issue from happening, but it is only a good idea to try this if you have a fairly simple home setup (i.e. just devices that need to access the internet), if you have devices that need to talk to each other and rely on your router to provide local DNS for the devices to find each other, then trying this workaround is probably not appropriate, as it may stop those devices from being able to see each other.


If you did want to try changing settings on your router then let me know and I'll post the details, you can easily undo the change if necessary.


The TalkTalk staff on this community will be able to help, they will hopefully be able to respond to this post tomorrow.