Default number of dns retries doubled
Ángel González
keisial@gmail.com
Fri Aug 16 11:33:00 GMT 2013
resolv.conf(5) contains:
> attempts:n
> sets the number of times the resolver will
> send a query to its name servers before giving up and returning an
> error to the calling application. The
> default is RES_DFLRETRY (currently 2, see
> <resolv.h>). The value for this option is silently capped to 5.
My /usr/include/resolv.h does indeed contain
> # define RES_DFLRETRY 2 /* Default #/tries. */
/etc/resolv.conf only contains two nameserver lines.
However, traffic sniffing shows 8 dns requests before giving up (4 to
each nameserver).
And a simple program confirms it:
> #include <resolv.h>
>
> int main() {
> res_init();
> printf("Timeout: %d\n", _res.retrans);
> printf("Attempts: %d\n", _res.retry);
> return 0;
> }
Output:
> Timeout: 5
> Attempts: 4
Any idea for this discrepancy?
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