Resolve dns problem with multiply fastify servers started in localhost

Hi guys,

I have an always replicable issue when I start two different fastify process in localhost, the first application server started with fastify calls the second one and him request an api served under vpn, if im not connect to the vpn in that moment, I have an ESERVFAIL error:

> [2025-02-11T22:50:51.319 +0100] WARN: response errored
> err: {
> "type": "Error",
> "message": "queryAaaa ESERVFAIL localhost",
> "stack":
> Error: queryAaaa ESERVFAIL localhost
> at QueryReqWrap.onresolve [as oncomplete] (node:internal/dns/promises:173:17)
> "code": "ESERVFAIL",
> "syscall": "queryAaaa",
> "hostname": "localhost"
> }

this error remains in dns cache without options to clear or its only me cant find the option to clear dns cache in fastify?

Happy to help with PR, but I wanna be sure this case is not covered

ps: this happening in local only