+++
date    = "2023-12-21T22:39:52+00:00"
lastmod = "2023-12-21T22:39:52+00:00"
tags    = [ "linux" ]
+++

I saw something peculiar the other day. Hallucination? The
[microsoft.com](https://www.nslookup.io/domains/microsoft.com/dns-records/)
domain was serving up 192.168.1.0 and 192.168.1.1 as
[A records](https://simple.wikipedia.org/wiki/A_record) in a 7 address round
robin.

That's a spooky reminder to check your
[rebinding](https://en.wikipedia.org/wiki/DNS_rebinding#Protection) setup ---
that is, if you're playing with fire ({{< abbr DNS "Domain Name System" >}}).

For example,
[unbound](https://nlnetlabs.nl/documentation/unbound/unbound.conf/#:~:text=Give%20IPv4)
with `private-address` and `private-domain`. Then
[test if DNS rebinding](https://lock.cmpxchg8b.com/rebinder.html) is possible.