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Re: Re: Case Sensitivity

2004-07-31 09:47:34
Yes, I read your postings on SPF-Help and the reason that I then posted on 
SPF-Discuss was to get a more authoritative answer.  Your postings are just 
opinion and speculation.  There are members on the SPF-Discuss list who are 
more familiar with best practices and actual RFC specifications.  In addition, 
the author of libspf2 is on the SPF-Discuss list and was hoping that he could 
comment as well....

Marc

From: "Chris Haynes" <chris(_at_)harvington(_dot_)org(_dot_)uk>
Date: 2004/07/31 Sat PM 12:26:06 EDT
To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
Subject: Re: [spf-discuss] Case Sensitivity

As I said on spf-help, it's my understanding that people are allowed to use
upper-case wherever and wherever they wish in domain names contained in eMail
addresses. The identification of the domains is intended to be 
case-insensitive.

AFAIK, DNS systems handle domain names in a 'canonical' lower-case form.

I therefore think that the problem is in SPF:  It should normalize the domain
names received in SMTP messages to lower-case before undertaking SPF tests.

(And were I implementing an SPF tool, I would also ensure that any domain 
string
I obtained from DNS was also in lower-case - just to make sure).

As I can't see this lower-case normalization required  in the SPF ietf-drafts,
it looks to me like it is an omission from the SPF specs, not a tool
implementation error.

Chris Haynes



 <marc(_at_)alaia(_dot_)net>alerted everyone:

Hey, everyone.  A situation has come up on the SPF-Help list where a 
receiver
is rejecting inbound mail from a domain and it turns out that the problem is
case sensitivity.  A test using libspf2 verified that libspf2, at least, is 
case
sensitive.

Is this an implementation issue or a spec issue, or not an issue at all?  
What
I mean is:
- Are all DNS-related issues supposed to be case-insensitive, so this does 
not
need to be in the spec, but certain implementations have implemented it wrong?
- Are all DNS-related issues not specified, so the SPF spec needs to say?
- Or do people need to be aware that case may cause their mail to be 
rejected?

Evidence presented below....

Regards,
Marc Alaia

srs# spfquery -debug -ip 216.39.67.112 -sender cwjobs-
e2-27265112(_at_)ProcessRequest(_dot_)com -helo DAL1BS110.PROCESSREQUEST.COM
spf_dns_null.c:64    Debug: DNS pre-cache lookup:  ProcessRequest.com TXT
(16)
spf_dns_resolv.c:144 Debug: DNS resolv looking for:  ProcessRequest.com 
TXT
(16)
spf_dns_null.c:94    Debug: DNS pre-cache found:   ProcessRequest.com TXT
(16)  TTL: 1800  RR found: 1  herrno: 0  source: resolv
spf_get_spf.c:116    Debug: found SPF record: v=spf1 ptr -all
spf_dns_null.c:64    Debug: DNS pre-cache lookup: 
112.67.39.216.in-addr.arpa
PTR (12)
spf_dns_resolv.c:144 Debug: DNS resolv looking for: 112.67.39.216.in-addr.
arpa  PTR (12)
spf_dns_null.c:94    Debug: DNS pre-cache found: 
112.67.39.216.in-addr.arpa
PTR (12)  TTL: 1800  RR found: 1  herrno: 0 source: resolv
spf_eval_id.c:551    Debug: found 1 PTR records for 216.39.67.112 (herrno:
0)
spf_dns_null.c:64    Debug: DNS pre-cache lookup: 
dal1bs110.processrequest.
com  A (1)
spf_dns_resolv.c:144 Debug: DNS resolv looking for:
dal1bs110.processrequest.
com  A (1)
spf_dns_null.c:94    Debug: DNS pre-cache found: dal1bs110.processrequest.
com  A (1)  TTL: 30  RR found: 1  herrno: 0 source: resolv
spf_eval_id.c:569    Debug: 0:  found 1 A records for dal1bs110.
processrequest.com  (herrno: 0)
spf_eval_id.c:586    Debug: 0: 0:  found 216.39.67.112
spf_eval_id.c:597    Debug: ProcessRequest.com ==
dal1bs110.processrequest.com
spf_eval_id.c:605    Debug: sRequest.com == srequest.com SPF header:
version: 1  mech 2/4  mod 0/0  len=8
SPF record:  v=spf1 ptr -all
err = No errors (0)
err_msg =
 fail
Please see
http://spf.pobox.com/why.html?sender=cwjobs-e2-27265112%40ProcessRequest.com&ip=
216.39.67.112&receiver=spfquery
spfquery: domain of ProcessRequest.com does not designate 216.39.67.112 as
permitted sender
Received-SPF: fail (spfquery: domain of ProcessRequest.com does not
designate
216.39.67.112 as permitted sender) client-ip=216.39.67.112; envelope-
from=cwjobs-e2-27265112(_at_)ProcessRequest(_dot_)com; 
helo=DAL1BS110.PROCESSREQUEST.COM;

Maybe it's the case (ProcessRequest.com vs processrequest.com) that's 
giving
problems here?? If that's not it, i see no reason why it should fail.

Ah yes, it definatelly is case related:

srs# spfquery -ip 216.39.67.112 -sender
cwjobs-e2-27265112(_at_)processrequest(_dot_)com
-helo DAL1BS110.processrequest.com pass

spfquery: domain of processrequest.com designates 216.39.67.112 as 
permitted
sender
Received-SPF: pass (spfquery: domain of processrequest.com designates
216.39.67.112 as permitted sender) client-ip=216.39.67.112; envelope-
from=cwjobs-e2-27265112(_at_)processrequest(_dot_)com; 
helo=DAL1BS110.processrequest.com;



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