For the last week I've been experiencing intermitent connection issues.
Whenever the problems manifest themselves I can still make a wireless connection to my HomeHub 4, but cannot connect to the outside world.
I have done a factory reset (paper-click job) to no availe.
After a lot of experimentation I have found that if I specify Google's DNS server (188.8.131.52) rather than use DHCP then the connection from my laptop is rock solid. The problem is, I can't over-ride the DNS server on every portable device in the house (Squeezebox, Android tablets / phones, iPods/iPads - you get the idea).
HH4 Internet Config page shows
I don't know if these are right or not - I assume so because I cannot find anyway of overriding them.
I've done a few tests using the DNS servers you mentioned and they seem ok to me, although I did only try for 5 minutes or so.
They're both valid BT DNS servers, but you could try restarting your router a few times to see if it is assigned IP addresses and DNS servers from a different pool.
Looking at your other thread I see you are on Infinity. Have you tried restarting the modem and the home hub, to see if you can pick up different DNS servers?
You cannot override the ones in the home hub, which are obtained automatically.
When you look at the HH4 Internet configuration page, what is it showing for your broadband network IP address?
Does it match your public IP address?
Yes Keith, Broadband network IP address matches what whatsmyip.org shows as being my address
Then its difficult to see what the issue is. Do you get DNS failures on all of your devices, and do you get failures if you connect using an Ethernet cable, and not wireless?
"After a lot of experimentation I have found that if I specify Google's DNS server (184.108.40.206) rather than use DHCP then the connection from my laptop is rock solid."
Did you try rebooting your router a couple of times like we suggested to see if you are assigned different DNS servers?