Multiple DNS Forwards
Dave Walsh
dave_j_walsh at keane.com
Wed May 24 19:20:55 UTC 2000
Below is the content of my original question and the answer (from the BIND
archives). Your solution worked great. However, our partner company has now
expanded or decentralized and they also have more than just partner.com
names to resolve. They now have hal.us.partnerco.com. I tried putting in
another entry in my named.conf, but it doesn't seem to resolve hosts in
hal.us.partnerco.com, but partner.com does still work.
Any ideas?
TIA
Dave
EXAMPLE: named.conf
=====================
options {
directory "/var/named";
forwarders { 227.252.18.10; };
forward only;
query-source address * port 53;
};
zone "0.0.127.IN-ADDR.ARPA" in {
type master;
file "db.127.0.0";
notify no;
};
zone "mycompany.ca" in {
type master;
file "db.mycompany";
};
** NOTE: I CAN RESOLVE HOSTS IN PARTNER.COM
zone "partner.com" {
type forward;
forward only;
forwarders { 158.138.120.22; }
}
** NOTE: I CAN'T RESOLVE HOSTS IN HAL.US.PARTNERCO.COM
zone "hal.us.partnerco.com" {
type forward;
forward only;
forwarders { 158.138.120.22; }
}
zone "57.168.192.IN-ADDR.ARPA" in {
type master;
file "db.192.168.57";
};
zone "0.1.10.IN-ADDR.ARPA" in {
type master;
file "db.10.1.0";
};
zone "0.30.10.IN-ADDR.ARPA" in {
type master;
file "db.10.30.0";
};
zone "148.208.198.IN-ADDR.ARPA" in {
type master;
file "db.198.208.1481";
};
// zone "." in {
// type hint;
// file "db.cache";
// };
END NAMED.CONF
ORIGINAL CORRESPONDENCE
There is really no such thing as "conditional" forwarding in BIND 8. There
is, however, "selective" forwarding. The difference is more than semantic:
selective forwarding works *unconditionally*, i.e. has no relation to
events or state, but is specified on a zone-by-zone basis, i.e. all queries
in a specific zone X should be forwarded to a specific set of servers Y, Z,
etc.. In your case, you'd set up a zone of type "forward" for your business
partner's domain, let's call it "partner.com". And also in the zone
definition you'd specify "forward only" and a "forwarders" clause
containing the addresses of the partner's nameservers. So it would look
something like:
zone "partner.com" {
type forward;
forward only;
forwarders { x.x.x.x; y.y.y.y; };
}
In your situation, selective forwarding would probably be better than
conditional forwarding anyway, which would waste time and resources sending
queries to the wrong places.
A couple of other alternatives to consider, depending on your performance
characteristics and/or requirements, or redundancy requirements, would
include stub or slave zones.
- Kevin
Dave_Walsh wrote:
> We are a satellite organization of our parent organization. At present,
>
> all of our Win95 PCs point to my local DNS server with a forward
> statement
> to our parent organization's DNS server for name resolution. In other
> words, anything not resolved locally, will be forwarded to our corporate
>
> head office (where our Internet access is also). We've recently
> acquired a
> project with a business partner that requires only our location to have
> access to the partner's DNS server so I can resolve names in their name
> space.
>
> What's the best approach to accomodate all my needs? I must be able to
> resolve local IP names, corporate names in the corporate WAN, Internet
> names (via corporate) & the names at our new business partner. Can I
> put on a second
> forwarder statement on my local DNS server that will effectively say,
> "if
> you can't resolve it yourself, try the corporate DNS, if you can't
> resolve
> it there, try the partner DNS?".
>
> Mr. DNS says that conditional forwarding of BIND 8.2 will do it. I'm
> pretty new to DNS. Can someone please advise.
>
> TIA
>
> Dave
>
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