+++ 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.