[nsd-users] nsd can't bind udp socket: Address already in use

Paul Wouters paul at nohats.ca
Wed Jul 10 15:04:28 UTC 2013

On Wed, 10 Jul 2013, zongo saiba wrote:

> I have installed 'unbound' and it works nicely on my client (test purpose) - 
> Client is MacBook Air.
> I have installed NSD (will be in replacement of BIND) on said client.
> All is good but when i try to start NSD
> Error --> nsd can't bind udp socket: address already in use.
> Everything is configured to bind to

> So I understand that 127.0.01 is just booked by other processes and in 
> particular unbound.
> What troubles me is how to solve that issue ?

that depends on what you want to do.

You can make unbound or nsd listen on another IP address or port. But
clearly if you use unbound for resolving, you cannot replace it with
nsd, as your resolving would break.

If you want to use nsd to host some domains, and use unbound for
resolving the normal way with a special forward to those nsd domains,
you should run nsd on another port like 5353 and configure unbound
forward zones to point to at 5353 for those zones.


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