[Dnsmasq-discuss] split DNS, multiple --local entries and secondary DNS

Martijn Brinkers (List) martijn.list at gmail.com
Thu May 24 08:38:40 BST 2007



A company has a split DNS ie. they have an internal DNS containing only
records for private internal domains and an external DNS containing only
public records. Normally you would have the internal DNS forward unknown
requests to the external DNS but that's not possible in this situation.


The problem is that our machine need to lookup internal private domains as
well as external public domains. It seems this is not possible with the
default Linux resolvers because when a DNS server reports a negative result
the secondary DNS is never queried (which is normal). 
The way we solved it is by using the following DNSMasq option:

-S, --local,

We can now specify that lookups for an internal domain should go to the
internal DNS server and lookups for an external domain will go to the
default external DNS servers.

This seems to fix the split DNS problem. We only have one problem left.
There are two internal DNS servers. The primary and the secondary. When the
primary internal DNS stops answering queries all internal requests should go
to the secondary internal DNS server.

What we have tried is to add multiple 'local' options with the same domain
but with a different <ipaddr> but this seems not to work. Only the first
entry is used and if the lookup fails it does not try the secondary internal
DNS server but falls back on the external DNS.

Can someone help me to get this working? Or is this an impossible request?

Martijn Brinkers

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