[dns-operations] service showing (last) resolver's IP ?

[bert hubert]

On Sat, Dec 09, 2017 at 12:52:13PM +0300, Frank Habicht wrote:
> There MUST be somewhere one (or more) service(s) that can tell me from
> what source IP the resolver (or the last one in a chain) queries the
> authorities. I guess answering a query for TXT.

You found an answer already, but let me promote our service which I think
has one unique feature: separate v4 and v6 domains.

We host the following records

dig -t a whoami.v4.powerdns.org
dig -t aaaa whoami.v6.powerdns.org

dig -t txt whoami.v4.powerdns.org
dig -t txt whoami.v6.powerdns.org

dig -t txt whoami-ecs.v4.powerdns.org
dig -t txt whoami-ecs.v6.powerdns.org

The v4 names can only be resolved over IPv4, the v6 names only over IPv6.

The ECS variants also tell you if there was embedded EDNS Client Subnet.

You can also try:

dig -t txt latlon.v4.powerdns.org

This returns where the Maxmind database thinks your resolver is coming from.
The first one that asks 'why not a LOC record' gets to contribute the code
to do this. Conversion from fractional degrees to split out in minutes and
seconds turns out to suck.

	Bert