Changing to non-Plusnet DNS Resolver on BT Home Hub

[#1]

Hi,

Anyone else experienced problems changing from default Plusnet DNS servers, to others such as Google or OpenDNS?

I have a BT HomeHub, so unable to change the DNS servers on there. But if I try to override it and query 8.8.8.8 from any machine on my network, the connection times out. The firewall on the client machine is off, and firewall on the router is off, and the firewall on my Plusnet account is also off. But something is intercepting and blocking UDP 53 responses to my queries. Either the BT HomeHub, or Plusnet.

James

[#2]

You can't change the DNS setting on most BT HH's. You can on some of the Business models.

[#3]

Yeah, I get that. That isn't my issue. I can't query non-Plusnet DNS servers. Something is blocking the traffic. I don't remember having this issue when I was with BT, so leads me to think Plusnet are blocking UDP 53 to anything accept their own DNS servers.

jjrbg-MacBook-Pro:~ jjrbg$ host bbc.co.uk 212.159.6.9

Using domain server:

Name: 212.159.6.9

Address: 212.159.6.9#53

Aliases:

bbc.co.uk has address 151.101.192.81

bbc.co.uk has address 151.101.64.81

bbc.co.uk has address 151.101.128.81

bbc.co.uk has address 151.101.0.81

bbc.co.uk has IPv6 address 2a04:4e42:200::81

bbc.co.uk has IPv6 address 2a04:4e42::81

bbc.co.uk has IPv6 address 2a04:4e42:600::81

bbc.co.uk has IPv6 address 2a04:4e42:400::81

bbc.co.uk mail is handled by 20 cluster1a.eu.messagelabs.com.

bbc.co.uk mail is handled by 10 cluster1.eu.messagelabs.com.

jjrbg-MacBook-Pro:~ jjrbg$ host bbc.co.uk 8.8.8.8

;; connection timed out; no servers could be reached

jjrbg-MacBook-Pro:~ jjrbg$ host bbc.co.uk 208.67.222.222

;; connection timed out; no servers could be reached

[#4]

I can query plenty of external nameservers using the PN HubOne so I don't think it's a plusnet issue, it's more likely to be the BT device as my experience with BT many years ago was one of arrogance and being difficult towards customers.

If you download a program called DNS Jumper, you can perform a "fastest" test which will let you test a whole load of nameservers for response times. If you literally get no reply from any of them then you can confirm that there is something actively blocking your resolution requests.

An interesting sidenote is that the DNS protocol is the only one to use UDP and TCP for resolution. AFAIK the windows default dns client only uses UDP so it might be possible to find another one that uses TCP instead which your OS can rely on. Not sure as i've never tried it but it might be something to look into.

[#5]

@jjrbg, like 7up, there is nothing wrong here using google’s DNS on Plusnet’s Fibre

iMac:~ Mook$ host bbc.co.uk 8.8.8.8
Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases:

bbc.co.uk has address 151.101.128.81
bbc.co.uk has address 151.101.64.81
bbc.co.uk has address 151.101.192.81
bbc.co.uk has address 151.101.0.81
bbc.co.uk has IPv6 address 2a04:4e42:600::81
bbc.co.uk has IPv6 address 2a04:4e42::81
bbc.co.uk has IPv6 address 2a04:4e42:200::81
bbc.co.uk has IPv6 address 2a04:4e42:400::81
bbc.co.uk mail is handled by 20 cluster1a.eu.messagelabs.com.
bbc.co.uk mail is handled by 10 cluster1.eu.messagelabs.com.

On your iMac you could try:

host -T bbc.co.uk 8.8.8.8 

to enable TCP Mode or try :

host -R X bbc.co.uk 8.8.8.8

where X is the number of UDP retries to see if any of these produce different results.

[#6]

Here's an interesting response:-

host plus.net 8.8.8.8
Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases:

plus.net has address 212.159.8.2
plus.net has address 212.159.9.2
plus.net mail is handled by 10 smtpe1.intersmtp.com.
plus.net mail is handled by 10 smtpb1.bt.com.