Bug #81787 for Net-DNS: NXDOMAIN is no longer reported by $r->errorstring

Fri Dec 07 20:21:26 2012 Mark.Martinec [...] ijs.si - Ticket created

Subject:

NXDOMAIN is no longer reported by $r->errorstring

Net::DNS 0.69 (and 0.70) no longer return error in errorstring() in case the Net::DNS::Resolver::query() comes back empty-handed (non-existent domain, packet is returned with no answer section, header->rcode is NXDOMAIN): $ perl -le 'use Net::DNS; $r=Net::DNS::Resolver->new; $resp=$r->query("_adsp._domainkey.xxx.sa-test.spamassassin.org"); printf("resp=%s, errstr=/%s/\n", defined $resp ? $resp : "UNDEF", $r->errorstring)' 0.69, 0.70 -(incorrect): resp=UNDEF, errstr=// 0.68 - (correct): resp=UNDEF, errstr=/NXDOMAIN/ (btw, this breaks Mail::DKIM handling of ADSP for non-existent domains)

Sat Dec 08 09:12:42 2012 rwfranks [...] acm.org - Correspondence added

From:

rwfranks [...] acm.org

On Fri Dec 07 20:21:26 2012, Mark.Martinec@ijs.si wrote: Show quoted text

> Net::DNS 0.69 (and 0.70) no longer return error in errorstring() > in case the Net::DNS::Resolver::query() comes back empty-handed > (non-existent domain, packet is returned with no answer section, > header->rcode is NXDOMAIN): > > $ perl -le 'use Net::DNS; $r=Net::DNS::Resolver->new; > $resp=$r->query("_adsp._domainkey.xxx.sa-test.spamassassin.org"); > printf("resp=%s, errstr=/%s/\n", > defined $resp ? $resp : "UNDEF", $r->errorstring)' > > 0.69, 0.70 -(incorrect): > resp=UNDEF, errstr=// > > 0.68 - (correct): > resp=UNDEF, errstr=/NXDOMAIN/ > > (btw, this breaks Mail::DKIM handling of ADSP for non-existent domains)

errorstring() is not intended to be a substitute for header->rcode. It only contains the RCODE if the resolver completed the retry sequence for all nameservers, as the only evidence it has which might identify the error. A query which returns NXDOMAIN is a proper response which indicates that there is no RR with the specified name. This is not an error. errorstring() is used to report exceptions and error conditions which prevent proper functioning of the resolver itself.

Sat Dec 08 09:12:44 2012 The RT System itself - Status changed from 'new' to 'open'

Sat Dec 08 10:08:34 2012 Mark.Martinec [...] ijs.si - Correspondence added

From:

Mark.Martinec [...] ijs.si

Show quoted text

> errorstring() is not intended to be a substitute for header->rcode. > It only contains the RCODE if the resolver completed the retry > sequence for all nameservers, as the only evidence it has which > might identify the error. > A query which returns NXDOMAIN is a proper response which indicates > that there is no RR with the specified name. This is not an error.

That would make sense when used with a send() method, which does return a 'header' object and $r->header->rcode can be examined. But when query() is used, it returns undef when there are no answer sections, so rcode can't be examined. The query() method is to be used like: $r->query(...) or die "Can't do it: ".$r->errorstring I suppose.

Sun Dec 09 15:44:40 2012 rwfranks [...] acm.org - Correspondence added

From:

rwfranks [...] acm.org

On Sat Dec 08 10:08:34 2012, Mark.Martinec@ijs.si wrote: Show quoted text

> But when query() is used, it returns undef when there are no answer > sections, so rcode can't be examined. The query() method is to be > used like: $r->query(...) or die "Can't do it: ".$r->errorstring > I suppose.

I get the picture. If I can put it back, I will, but you must not expect always to get an RCODE mnemonic. errorstring() will return other forms of bad news if the resolver trips over bad data or OS problems outside its control.

Sun Dec 09 21:31:50 2012 Mark.Martinec [...] ijs.si - Correspondence added

From:

Mark.Martinec [...] ijs.si

Show quoted text

> I get the picture. > If I can put it back, I will, but you must not expect always to get an > RCODE mnemonic. errorstring() will return other forms of bad news > if the resolver trips over bad data or OS problems outside its control

Thank you! Replacing query() by send() was already discussed for the Mail::DKIM project for other reasons and will probably materialize in the next release, this incompatibility adds another incentive for the transition and for more concise DNS error results handling.

Mon Dec 10 16:23:24 2012 NLNETLABS [...] cpan.org - Correspondence added

Patch committed in trunk and it will be in 0.71.

Mon Dec 10 16:23:25 2012 NLNETLABS [...] cpan.org - Status changed from 'open' to 'resolved'