yungmichael / zone-nameservers

Walk the DNS tree to find which nameservers a particular zone (or "domain") uses. Mimics "dig +trace", but in Go.

zone-nameservers

Walk the DNS tree to find which name servers a particular zone uses. Mimics "dig +trace", but written in Go as an experiment.

Building

After a git clone;

$ go build
$ ./zone-nameservers YOURDOMAIN.TLD

Examples

Here's what it looks like for dnsspy.io.

./zone-nameservers dnsspy.io
Retrieving list of root nameservers:
 - a.root-servers.net.
 - b.root-servers.net.
 - c.root-servers.net.
 - d.root-servers.net.
 - e.root-servers.net.
 - f.root-servers.net.
 - g.root-servers.net.
 - h.root-servers.net.
 -> i.root-servers.net.
 - j.root-servers.net.
 - k.root-servers.net.
 - l.root-servers.net.
 - m.root-servers.net.


Finding nameservers for zone 'io.' using parent nameserver 'i.root-servers.net.'
 - a0.nic.io.
 - b0.nic.io.
 - c0.nic.io.
 - ns-a1.io.
 - ns-a2.io.
 -> ns-a3.io.
 - ns-a4.io.


Finding nameservers for zone 'dnsspy.io.' using parent nameserver 'ns-a3.io.'
 - ns1.nucleus.be.
 - ns2.nucleus.be.
 - ns3.nucleus.be.
 - ns4.nucleus.be.

The arrow represents which nameserver from the parent was used to query for details of the child zone.

Why?

Why not just query directly for NS records, you ask? Not everyone keeps those up-to-date and they often return outdated or wrong information, as nameservers change without modifying the NS records to reflect that.

In other words: the only absolutely way to find our which nameservers a particular zone uses, you have to walk the DNS tree.

Credits

This code is initially based on the check-soa script by miekg.