[conspire] Unbound and DHCP on home computer

Rick Moen rick at linuxmafia.com
Mon Dec 14 18:36:20 PST 2009


Quoting Nick Moffitt (nick at zork.net):

> Take a look at /etc/dhcp3/dhclient.conf, and you should see an entry
> like the following:
> 
> 	#prepend domain-name-servers 127.0.0.1;
> 
> Uncomment that, and you should be golden, with localhost trumping any
> remote DNS servers.

That has the merit of simplicity.  I like it.  

Just to be clear, this doesn't prevent ISC DHCP (DHCP client) from _also_
putting into /etc/resolv.conf various "nameserver nn.nn.nn.nn" lines,
_but_, fortunately, the resolver (your DNS client library inside glibc) 
reads "nameserver" lines in the order presented, and performs the
queries in that order.  If the first entry's IP times out, then the
query is repeated on the second entry, and so on, up to a maximum number
of retries.

I long ago got wary of assuming that multiple lines of anything in DNS
will get processed in the order you would normally assume.  For example,
order of NS entries in a DNS zone has no importance, and neither does 
order of Nameserver lines in a domain's whois record.  However, "man
resolv.conf" points out that this is an exception to the general
pattern.





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