My Vigor 2830n has been working brilliantly on BT Infinity for a few months, connected to the Openreach modem via WAN2. However, since Sunday all webpages have timed out with a DNS error. I can access websites by their IP address so the actual "internet connection" is OK through the 2830n.

Also I can replace the 2830n with the old BT Home hub 2 and all works OK. Interestingly the DNS servers listed in the Home Hub advanced settings page can't be pinged via the Home Hub or the 2830n, so I wonder if they really are the correct DNS server addresses or if the BT Home Hub and/or Openreach modem is using some secret DNS server that it won't reveal the address of and therefore the 2830n can't connect to it?

Interestingly if I set an alternative DNS server address manually on my PCs (e.g. Google's 8.8.8.8) then this appears to work through the Home Hub but not through the 2830n. I can ping 8.8.8.8 through both routers but nslookup fails with a timeout through the 2830n but works fine through the BT Home Hub.

It almost looks like something in the BT network is filtering out DNS requests to particular addresses and is only allowing through some secret address that the Home Hub and/or modem knows about.

Is anyone else having this type of problem since the supposed BT "network upgrade" over the weekend. I'm in Basingstoke BTW.

Thanks!
Simon.

Update ...

D'OH!!!!

In the Firewall Filter Setup page, that first built in "demo" filter "xNetBios -> DNS" had accidentally been ticked, thereby blocking access from anything on the LAN to DNS servers it seems.

Cheers!
Simon.

HI Simon

I see you are using the 2830N with openreach modem - I dont suppose you could guide me through how you set it up please?
I am struggling to work out even where to start!

Any help would be appreciated.

Thanks
Richard

strouds wrote:

In the Firewall Filter Setup page, that first built in "demo" filter "xNetBios -> DNS" had accidentally been ticked, thereby blocking access from anything on the LAN to DNS servers it seems.

Cheers!
Simon.

That's unlikely to be the cause of your problem as that rule should not block pure (port 53) DNS requests, only internal NETBIOS requests trying to resolve via external DNS queries. That rule should really be left enabled under 99.9% of circumstances.

Trick97 wrote: HI Simon

I see you are using the 2830N with openreach modem - I dont suppose you could guide me through how you set it up please?
I am struggling to work out even where to start!

Any help would be appreciated.

Thanks
Richard

Hi Richard,

It was very easy to set up for the Openreach modem (original version - I have not had mine replaced yet) ...

In WAN>General Setup I have:
... Gone into WAN1 and WAN3 pages and set them to Enabled = NO
... Gone into WAN2 page and set:
... Enabled = YES
... Display Name = btinfinity
... Physical type = Auto Negotiation
... Active mode = Always On

In WAN>Internet Access I have set:
...WAN2 to access mode PPPoE

In WAN2 Details page I have set:
... "Enable"
... username = bthomehub@btbroadband.com
... password = anything
...PPP authentication = PAP or CHAP
... Fixed IP = NO

and it all just worked.

Regards,
Simon.

Not using Infinity, but I get sporadic periods of time when DNS doesn't seem to work. Power-cycling the router does seem to help.
Interestingly, some of these intervals seem to correspond with mail from the server reporting a UDP flood DOS attack. I wonder if something is making the router interpret DNS responses as an attack?

Does anyone have a similar issue, or any advice?