[nsd-users] NSD not reachable over IPv6 without ip-address option

[Pim Kunis]

Hi,

I have a dual-stack IPv4/IPv6 server on which I run NSD. However, 
without adding the "ip-address" option in nsd.conf, NSD does not respond 
to IPv6 queries. It does respond to IPv4 queries. Also, it does respond 
to requests from the same machine to ::1.

Below you can see that the NSD is indeed listening to UDP port 53 on 
IPv6 on the wildcard address:

> root at lewis:/etc/nsd# ss -ulpn sport inet6:53
> State                 Recv-Q Send-Q                                 
> Local Address:Port                                 Peer 
> Address:Port                Process
> UNCONN                0 0 [::]:53 [::]:*                    
> users:(("nsd: server 4",pid=16052,fd=4),("nsd: server 
> 3",pid=16051,fd=4),("nsd: server 2",pid=16050,fd=4),("nsd: server 
> 1",pid=16049,fd=4),("nsd: main",pid=16048,fd=4),("nsd: 
> xfrd",pid=16046,fd=4))

Does anybody know what could be the problem?

Kind regards,

Pim Kunis