Hi,

> [...]
> Which implementation of nslookup is this? Busybox? It would probably
> be useful to hear thoughts on it from their side.
assuming the OP is using standard OpenWrt nslookup, it is the "big" busybox
nslookup implementation, which is using the res_*() api and name lookup logic
borrowed from musl libc instead of the original "small" version fiddling with
the `_res` state directly (and being broken on musl libc due to that).

The proper course of action here is likely adapting the solution in
6c858d6fd4df8b5498ef2cae66c8f3c3eff1587b and porting it to the busybox "big"
nslookup code itself.

I agree that musl libc itself cannot do much more to ensure uniqueness of the
IDs generated by res_mkquery() and that it should be solved in the application
code itself in this case.

Regards,
Jo