[Libevent-users] dns server availability check / google.com

[Nick Mathewson]

On Wed, Feb 27, 2008 at 07:17:50AM +0100, Florian Lohoff wrote:
> 
> Hi,
> while looking into an async dns solution i found the code to recheck 
> dns servers in libevent. I dont think checking for google.com is a very
> good choice. In the past even ccTLDs have disappeared or start to
> disappear (.su, .dd, .yu) despite companys renaming, disappearing or
> having hicups.

Actually, looking for google.com isn't a problem here, if I understand
correctly.  Look at the code in nameserver_probe_callback: it accepts
either DNS_ERR_NONE _or_ DNS_ERR_NOTEXIST as an answer meaning that
the nameserver is running.  In other words, a nameserver that says
"there is no google" is considered just as "up" as a nameserver that
reports what we'd currently expect to see.

Does that seem like a sensible argument, or am I missing something?

yrs,
-- 
Nick