![Example Of Blocked eMail
Feb 20 11:58:04 ms1 postfix/policy-spf[3987]: Policy action=550 Please see
http://www.openspf.net/Why?s=helo;id=redithosting.co.uk;ip=5.2.18.104;r=ms1
.redit.co.uk
Feb 20 11:58:04 ms1 postfix/smtpd[2236]: NOQUEUE: reject: RCPT from
unknown[5.2.18.104]: 550 5.7.1 <yoqiihld@redithosting.co.uk>: Recipient
address rejected: Please see
http://www.openspf.net/Why?s=helo;id=redithosting.co.uk;ip=5.2.18.104;r=ms1
.redit.co.uk; from=<> to=<yoqiihld@redithosting.co.uk> proto=ESMTP
helo=<redithosting.co.uk>
Feb 20 12:26:08 ms1 postfix/policy-spf[6230]: Policy action=550 Please see
http://www.openspf.net/Why?s=mfrom;id=users@email.address;ip=95.105.89.221;
r=ms1.redit.co.uk
Feb 20 12:26:08 ms1 postfix/smtpd[2236]: NOQUEUE: reject: RCPT from
unknown[95.105.89.221]: 550 5.7.1 <support@redit.co.uk>: Recipient address
rejected: Please see http://www.openspf.net/Why?s=mfrom;id=
users@email.address;ip=127.0.0.1;r=ms1.redit.co.uk;
from=<AndrewMorgan@ufanet.ru> to=<support@redit.co.uk> proto=ESMTP
helo=<127.0.0.1.public.ip.address>](https://image.slidesharecdn.com/spflightning-190221121541/85/Sender-Policy-Framework-14-320.jpg)
Sender Policy Framework
- 1. Sender Policy Framework Help Protect Your Inbox From Basic SPAM Wordup Pompey 20th February 2019 Scott McKeown
- 2. What is SPF? • An eMail authentication method • An open standard • Simple to enable
- 3. Short History Of SPF • 2000 First mention of an SPF idea • 2002 SPF-like specification published • 2003 RMX & DMP specifications merged • 2004 Renamed to ‘Sender Policy Framework’ from ‘Sender Permitted From’ and MARID task group formed • 2005 MARID group collapsed and revert to ‘classic’ SPF idea • 2006 Experimental RFC published for SPF • 2014 RFC-7208 published
- 4. How does SPF Work? Write an eMail eMail Server SPF Record Check SPF Fail eMail Server SPF Pass
- 5. Where does it go? DNS Zone file as a Text (TXT) Entry.
- 6. SPF Record Make Up • Three Sections • Domain or Subdomain • SPF Version • The Mechanisms (Rules)
- 7. The Domain or Subdomain SPF Sections
- 9. The Mechanisms (Rules) • Prefix • + Pass • - Fail • ~ Softfail • ? Neutral • Can be applied to ANY of the SPF Mechanisms (Rules)
- 10. The Mechanisms (Rules) • all • ip4 • ip6 • a • mx • ptr • exists • include
- 11. Examples Allow domain's MXes to send mail for the domain, prohibit all others v=spf1 mx –all Allow any IPv6 address between 1080::8:800:0000:0000 and 1080::8:800:FFFF:FFFF v=spf1 ip6:1080::8:800:200C:417A/96 –all The current-domain is used v=spf1 a –all Use External Mail Server v=spf1 mx mx:deferrals.domain.com –all Include Other Domains SPF Rules v=spf1 include:example.com -all
- 12. Lets Write Our Domain Rules
- 14. Example Of Blocked eMail Feb 20 11:58:04 ms1 postfix/policy-spf[3987]: Policy action=550 Please see http://www.openspf.net/Why?s=helo;id=redithosting.co.uk;ip=5.2.18.104;r=ms1 .redit.co.uk Feb 20 11:58:04 ms1 postfix/smtpd[2236]: NOQUEUE: reject: RCPT from unknown[5.2.18.104]: 550 5.7.1 <yoqiihld@redithosting.co.uk>: Recipient address rejected: Please see http://www.openspf.net/Why?s=helo;id=redithosting.co.uk;ip=5.2.18.104;r=ms1 .redit.co.uk; from=<> to=<yoqiihld@redithosting.co.uk> proto=ESMTP helo=<redithosting.co.uk> Feb 20 12:26:08 ms1 postfix/policy-spf[6230]: Policy action=550 Please see http://www.openspf.net/Why?s=mfrom;id=users@email.address;ip=95.105.89.221; r=ms1.redit.co.uk Feb 20 12:26:08 ms1 postfix/smtpd[2236]: NOQUEUE: reject: RCPT from unknown[95.105.89.221]: 550 5.7.1 <support@redit.co.uk>: Recipient address rejected: Please see http://www.openspf.net/Why?s=mfrom;id= users@email.address;ip=127.0.0.1;r=ms1.redit.co.uk; from=<AndrewMorgan@ufanet.ru> to=<support@redit.co.uk> proto=ESMTP helo=<127.0.0.1.public.ip.address>
- 15. References • https://en.wikipedia.org/wiki/Sender_Policy_Framework • http://www.openspf.org/ • https://www.gov.uk/government/publications/email-security- standards/sender-policy-framework-spf • https://tools.ietf.org/html/rfc7208