31 Jan
2004
31 Jan
'04
8:58 a.m.
Hi Lionel,
On Sat, 31 Jan 2004, Lionel Elie Mamane wrote:
Well, in this case it also might have to do with quite heavy load
on the internal servers, which are rather old and slow machines,
doing much other stuff than just plain DNS.
Well, there are delegations for subdomains to DNS servers on the
internal network. As soon as I activate "forward first", I won't
get those to answer my request for an MX, but I'll get the answer
as defined on the outside.
Example: dig mx sub1.domain.lu will query my internal server, who's
going to refer me to the DNS for that sub1.domain.lu subdomain, and
I'll get mail.sub1.domain.lu as MX (tried from an internal box).
With forward first, I'll get the external mail exchanger for
*.domain.lu. All in all, this will cause mail loops (between the
internal and external mail servers), which obviously isn't wanted.
Oh, the internal servers are still running bind8, in case it matters.
Let's
suppose I have a network with DMZ, with external and internal
DNS servers, with different definitions for my domain in both
Now, for whatever reason, my internal servers are
slower to
resolve external addresses than the external ones,
Probably because the external ones (your ISP's, I guess) often already
have the answer in their cache, while yours must do full resolution. and I'd
like to use those as forwarders, for stuff other than my own
domain (and subdomains),
When I try to go through the "forward
first" option, it seems that
*all* requests go to the external DNS servers,
Err... I'm using such a setup, and I have never encountered any
problem. How did you "see" that all requests go to the external DNS
servers? I checked with tcpdump, a query for an internal name
doesn't generate
any DNS traffic to the outside. Here is my named.conf:
Maybe it is because not everything is defined on those internal
servers, but partly delegated to others (on the internal network).
[snip config]
Thanks for the input anyway!
Apropos, I saw you're already configured for IPv6 - can you point
out a simple good nice introduction? I've checked some sites, but
those were either way too simple or way to deep (RFCs) into the
matter.
Thanks, Eric