Re: Name resolution and underscores? www.engadget.com

[Paul Ripke <stix%stix.id.au@localhost>]

On Mon, Jan 19, 2026 at 12:53:53PM +0000, RVP wrote:
> On Mon, 19 Jan 2026, Paul Ripke wrote:
> 
> > Do we check for underscores somewhere in name resolution?
> 
> Yes.
> 
> > I know that RFC 1035 disallows them from hostnames...
> 
> That's it.
> 
> > I had a quick browse of our code and nothing obvious stood out.
> 
> I think:
> 
> src/lib/libc/net/gethnamaddr.c:
> 
> gethostbyname() > gethostbyname_r() -> gethostbyname_internal() ->
> nsdispatch() -> _dns_gethtbyname() -> getanswer() ->
> 
> name_ok = res_hnok / maybe_ok()
> 
> This works--see resolv.conf(5):
> 
> # echo 'options no-check-names' >> /etc/resolv.conf

Ah! Perfect! Checking resolv.conf(5) completely slipped my mind.

One wonders, given the increasingly broken state of the internet, if
the default is sane? I see freebsd doesn't have this option, and
while linux has the option, it doesn't appear required in this case
(although I didn't investigate why)?

-- 
Paul Ripke
"Great minds discuss ideas, average minds discuss events, small minds
 discuss people."
-- Disputed: Often attributed to Eleanor Roosevelt. 1948.