Re: getaddrinfo(3) on numerical addresses

[uwe%stderr.spb.ru@localhost (Valery Ushakov)]

In gmane.os.netbsd.devel.network Edgar Fu? <ef%math.uni-bonn.de@localhost> wrote:

>> I suspect there's some misunderstanding.
>
> Yes. It's about numerical IPv4 addresses being looked up with an
> AF_INET6 hint.
>
> check_ping tries to figure out whether it needs to call ping6 (suppose 
> wer'e on a system where ping6 is different from ping).
> Suppose that check_ping is invoked without -4/-6 and with -H 1.2.3.4.
> Now check_ping tries to figure out whether the -H argument is a/resolves to 
> a IPv6 address. To do so, it checks whether getaddrinfo() on the -H argument 
> (which is 1.2.3.4) with an AF_INET6 hint succeeds. But this triggers a DNS 
> lookup.
> Given this is a monitoring system, who's job it is to detect server failures, 
> marking random servers/switches as dead while the resolver is going mad and
> so check_ping on their numerical IPv4 times out is not particularily useful.

BTW, isn't that exactly the argument that this program must use
AI_NUMERICHOST which guarantees that no name resolution will be
attempted?

-uwe