My PC gets its DNS from my ZyXEL P-660HW-T1 v2 router at 192.168.1.1
How can I determine where the router itself is getting its DNS?

I moved www.swiftys.org.uk between web hosting companies today. For a 
while my PC picked up the new address: 217.10.138.184
But then it reverted to the old address: 194.105.168.44

If I query AAISP's DNS at 217.169.20.20 then I get the new address.
if I query 192.168.1.1 then I get the old address.

So the router has reverted to an old address, so I'd like to know where 
it got it from, but I cannot find out what DNS server(s) the router 
itself is using.

It seems to have corrected itself now, but I'd still like to know if I 
can find the routers defined DNS servers.

-- 
Steve Swift
http://www.swiftys.org.uk/swifty.html
http://www.ringers.org.uk

On Tue, 22 Sep 2009 15:47:28 +0100, Swifty wrote:

> My PC gets its DNS from my ZyXEL P-660HW-T1 v2 router at 192.168.1.1
> How can I determine where the router itself is getting its DNS?

Via the web interface to my P660R-61C the Advanced Setup > LAN page
shows the primary and secondary DNS entries.

-- 
Cheers
Dave.

On Tue, 22 Sep 2009 17:10:23 +0100 (BST), "Dave Liquorice"
 wrote:

> On Tue, 22 Sep 2009 15:47:28 +0100, Swifty wrote:
>
>> My PC gets its DNS from my ZyXEL P-660HW-T1 v2 router at 192.168.1.1
>> How can I determine where the router itself is getting its DNS?
>
> Via the web interface to my P660R-61C the Advanced Setup > LAN page
> shows the primary and secondary DNS entries.

I believe he's asking what host is the PPP server on the WAN side.

Tony

Anthony R. Gold wrote:
> I believe he's asking what host is the PPP server on the WAN side.

No, he's asking what DNS servers the ZyXEL router uses when resolving IP 
names after connecting to AAISP.

This should be *so* easy to find in the routers Admin pages, but I've 
gone exhaustively through every link in every tab of every page and 
didn't notice it.

Put another way, when the router establishes its PPP link with AAISP, 
what decides which DNS systems will be used. This is sometimes specified 
in the router, sometimes supplied by the ISP. Either way, I can find no 
trace of what is being used.

Suppose, for an instant, that I wanted the router to use OpenDNS instead 
of what it is currently using (it may be using OpenDNS for all I know). 
I wonder how I'd go about specifying the DNS servers? Presumably the 
ones in use will be displayed somewhere nearby?

well, I may have found it, in the Network > LAN > DHCP setup there are a 
couple of addresses: 217.169.20.20 and 217.169.20.21 but I'm not 
convinced that these are necessarily the DNS servers used when my 
Windows system used the router (192.168.1.1) as its DNS server.
I can see that DHCP hosts on my LAN would get these addresses as 
suggested DNS servers.

-- 
Steve Swift
http://www.swiftys.org.uk/swifty.html
http://www.ringers.org.uk

In article ,
	Swifty  writes:
> Anthony R. Gold wrote:
>> I believe he's asking what host is the PPP server on the WAN side.
> 
> No, he's asking what DNS servers the ZyXEL router uses when resolving IP 
> names after connecting to AAISP.
> 
> This should be *so* easy to find in the routers Admin pages, but I've 
> gone exhaustively through every link in every tab of every page and 
> didn't notice it.

Looking in the logs of my router, A+A tell it to use
09/22/2009 15:28:26> PPP1: DNS Primary IP address is 217.169.20.20
09/22/2009 15:28:26> PPP1: DNS Secondary IP address is 217.169.20.21

However, as I run my own cacheing DNS server, I don't pass any DNS
requests to the router in the first place, so it's ignored by me.

-- 
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Swifty wrote:


> Suppose, for an instant, that I wanted the router to use OpenDNS instead
> of what it is currently using (it may be using OpenDNS for all I know).
> I wonder how I'd go about specifying the DNS servers? Presumably the
> ones in use will be displayed somewhere nearby?

There's a separate tab for DDNS and DynDNS under Advanced settings

fruit

Andy Carter wrote:
> There's a separate tab for DDNS and DynDNS under Advanced settings

The only item enabled on that page in my router is "Use Wan IP address" 
in "IP Address Update Policy" and I don't think that is relevant.

It seems as though AAISP send the router a pair of DNS server addresses, 
which it probably uses, but it doesn't display them anywhere. As it 
happens, they are the same pair of IP addresses configured by AAISP in 
the DHCP Setup panel (you have to admire AAISP's consistency) but I 
don't use DHCP.

Oh well, I get by without knowing the location of the Holy Grail; I can 
live happily in ignorance of what DNS servers my router is using.

-- 
Steve Swift
http://www.swiftys.org.uk/swifty.html
http://www.ringers.org.uk

Swifty wrote:

> Andy Carter wrote:
>> There's a separate tab for DDNS and DynDNS under Advanced settings
> 
> The only item enabled on that page in my router is "Use Wan IP address"
> in "IP Address Update Policy" and I don't think that is relevant.
> 
> It seems as though AAISP send the router a pair of DNS server addresses,
> which it probably uses, 

That's the usual way of doing it.

> but it doesn't display them anywhere. 

They'll probably appear in the logs - but you may have to telnet to see 
those.

> As it happens, they are the same pair of IP addresses configured by AAISP
> in the DHCP Setup panel (you have to admire AAISP's consistency) but I
> don't use DHCP.

Your network will use probably uses the router address as gateway and thus 
those DNS addresses.

fruit

On 2009-09-22, Andy Carter  wrote:
> Swifty wrote:
>
>> As it happens, they are the same pair of IP addresses configured by AAISP
>> in the DHCP Setup panel (you have to admire AAISP's consistency) but I
>> don't use DHCP.
>
> Your network will use probably uses the router address as gateway and thus 
> those DNS addresses.

Using the router as the default gateway doesn't automatically mean
machines on the network will use the same DNS servers as the gateway...

Swifty wrote:
> Andy Carter wrote:
>> There's a separate tab for DDNS and DynDNS under Advanced settings
> 
> The only item enabled on that page in my router is "Use Wan IP address" 
> in "IP Address Update Policy" and I don't think that is relevant.
> 
> It seems as though AAISP send the router a pair of DNS server addresses, 
> which it probably uses, but it doesn't display them anywhere. As it 
> happens, they are the same pair of IP addresses configured by AAISP in 
> the DHCP Setup panel (you have to admire AAISP's consistency) but I 
> don't use DHCP.

If you swapped your host addresses without previously reducing
ttl to a short period it just takes time for nameservers to get
back into sync as often the listed servers are used in rotation
and will not have refreshed information at same time.

I use a separate firewall that provides fixed ips etc via dhcp
to pcs on the lan and also is a dns server using aaisp dns ips
first but falling back to a full lookup if ever aaisp dns is
out. Using dhcp saves a lot of setting up of systems on lan,
but also has a few minor problems when unknown systems are
swapped about and uses up pool of addresses reserved for
dynamic allocation.

David

> 
> Oh well, I get by without knowing the location of the Holy Grail; I can 
> live happily in ignorance of what DNS servers my router is using.
>

David Lord wrote:
> If you swapped your host addresses without previously reducing
> ttl to a short period it just takes time for nameservers to get
> back into sync as often the listed servers are used in rotation
> and will not have refreshed information at same time.

Aha! That is almost certainly the source of my puzzlement. I knew it 
would take time for the new address to percolate through the system; I 
just never expected it to change back once it had come right. The 
rotation explains everything.

Quick! Let's all stop talking about this now I have an answer that keeps 
me quiet/happy! :-)

-- 
Steve Swift
http://www.swiftys.org.uk/swifty.html
http://www.ringers.org.uk