Watermarking and spoofed sender address

Robert Lopez rlopezcnm at gmail.com
Wed Mar 20 17:27:37 GMT 2013


If we do use SPF could there be something in the way we use it that it does
not help?  We added it as part of our out soucing student email.

>From http://www.kitterman.com/getspf2.py as of Wed Mar 20 2013:
SPF record lookup and validation for: cnm.edu
SPF records are primarily published in DNS as TXT records.

The TXT records found for your domain are:
v=spf1 include:_spf.google.com mx ~all

SPF records should also be published in DNS as type SPF records.

Type SPF records found for the domain are:
v=spf1 include:_spf.google.com mx ~all

Checking to see if there is a valid SPF record.

Results - Record may be valid, but ambiguous: v=spf1 records of both type
TXT and SPF (type 99) present, but not identical

Found v=spf1 record for cnm.edu:
v=spf1 include:_spf.google.com mx ~all

SPF record passed validation test with pySPF (Python SPF library)!

On Wed, Mar 20, 2013 at 10:20 AM, Kevin Miller <Kevin_Miller at ci.juneau.ak.us
> wrote:

> For what you’re trying to do, SPF is a better option.  ****
> ** **
>  ...Kevin
> --
> Kevin Miller
> Network/email Administrator, CBJ MIS Dept.
> 155 South Seward Street
> Juneau, Alaska 99801
> Phone: (907) 586-0242, Fax: (907) 586-4500
> Registered Linux User No: 307357 ****
> *From:* mailscanner-bounces at lists.mailscanner.info [mailto:
> mailscanner-bounces at lists.mailscanner.info] *On Behalf Of *Robert Lopez
> *Sent:* Tuesday, March 19, 2013 3:58 PM
> *To:* MailScanner discussion
> *Subject:* Watermarking and spoofed sender address****
> ** **
> I understand watermarking is to defend against "joe job blowback". I think
> I understand that blowback problem is when email is sent, using for example
> my address, to many other domains and all the flack (blow back) comes back
> to me.****
> I am wondering if this watermarking is of any use in a type of SPAM we now
> frequently see. It is where email is sent to a list of addresses, all at
> our domain, and the from address is also the first address in the address
> list. Everyone else thinks the first person sent it. Our gateways send such
> email to Exchange and any communication back to the sender is entirely
> within Exchange and never comes back through the gateways again.
> In this kind of SPAM I have always considered it of no use. Am I wrong in
> my thinking?
> ****
> --
> Robert Lopez
> Unix Systems Administrator
> Central New Mexico Community College (CNM)
> 525 Buena Vista SE
> Albuquerque, New Mexico 87106 ****
> --
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Robert Lopez
Unix Systems Administrator
Central New Mexico Community College (CNM)
525 Buena Vista SE
Albuquerque, New Mexico 87106
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