Re: [sheflug] DNS was Re: help with Broadband

["Morris, David (Allvac, UK)" <david [at] xxxxxxxxxxxx>]

> > I have contacted my ISP they have given me two DNS server 
> IP address.
> > I opened up mozilla and typed 192.168.0.1 to get to the router.
> > On the basic settings screen, it was marked  'get 
> automatically from 
> > ISP'  under DNS address.  I changed that to ''use these DNS 
> servers' 
> > and added the two IP addresses my ISP had given me to Primary DNS, 
> > secondary DNS, but it didn't make any difference.
> > 
> > When I have changed the resolv.conf file will I be using 'get 
> > automatically from ISP' or 'use these DNS servers'?
> 
> I'm not sure how this 'get automatically from ISP' works with 
> respect to an internal LAN and the issues you've been 
> experiencing.  All I am sure of with this is that the 
> /etc/resolv.conf files have to be the same in a network and 
> if you don't run DHCP on your LAN, how does the DNS 
> information propagate from the router inwards?  Does the 
> router offer a DNS service to the LAN?

You will probably find that the router has a DNS relay facility which is
or may be transparent to the user. You make a DNS query on the router.
If it's in cache it responds saving the ISP lookup. Otherwise, it makes
the query on the ISP and retruns you the result. In the days BB (Before
Broadband), it was clearly common with dialup connections not to have
the connection brought up on a DNS query 'cos there could be dozens of
them that weren't necessarily needed.

My IPCop firewall at home does exactly this. DHCP dishes out DNS
addresses that point to the firewall. BIND will operate in a caching
mode I believe.

-- 
David

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