Insights for Marketers Welcome and Goals

4/27/2007

Insights For Marketers

April 17, Boston Sheraton

Welcome And Goals

Craig Spiezle Director, Safety Technologies and Strategy Microsoft Corporation

Agenda

Introduction and Changing Rules of Deliverability Craig Spiezle, Director of Safety Technologies and Strategy

Introduction to Windows Live Hotmail Steve Bassler, Product Planner, Windows Live Hotmail

Optimizing e-mail deliverability into Windows Live Hotmail: Part I Brian Holdsworth, Senior Product Planner, Safety Technologies

Break

Optimizing e-mail deliverability into Windows Live Hotmail: Part II Kelly Sieben, Windows Live Escalation and Policy Manager

Evaluations, Drawings and Networking Access

General Housekeeping

Please turn off cell phones

Complete Evaluations forms – located in folder – place name on form to stand chance to win Zune!

Athletic bags for all attendees

Questions – 3x5 cards – will be answered after break

AOTA Summit - Single day registrations are available!

Changing Rules Of Deliverability Vectors, Volumes & Velocity

Chaf IP Reputation Can SPAM

Compromised Domain User Botnets PC’s Authentication Feedback

Phishing Brand Fraud ISP Policies Graymail

Image spam Mailing Lists

Unsubscribe Receiving networks and ISPs are under attack Message content is no longer king Impact to infrastructure Impact to user trust and confidence – our #1 priority

Trends

Growing level of sophistication Anti-virus to remove “competing” malware Pump and dump schemes Increased precision, profiling, testing and targeting They are become great direct marketers! The weakest link is the end user, falling prey to social engineering Consumer and business data at risk Impacting interactive marketing ROI

Lowlights

Spam – a plague of biblical proportions Volumes from bots increasing Image spam defeating traditional filters Phishing – increased precision Redefined from unsolicited email marketing to malicious and deceptive email and web sites Thriving black market for data Self-Policing – denial of service attacks against rivals Criminal underworld – competition driving down pricing Consolidation – increased intensively and severity

Highlights

Sender ID adoption has skyrocketed to 43% of legitimate email Supported by over 8 million domains Vibrant growth of the internet economy Online Holiday sales up 21% Online banking up 27% Business continue to realize productivity increases from the internet Phishing exploits seem to have leveled off Internet fraud to FBI down 10.4%

Introduction To Windows Live Hotmail Steve Bassler Product Planner Microsoft Corporation

Overview Of Microsoft’s Email Ecosystem

Corporate Servers and Services Enterprise-class availability and protection (with Forefront) Exchange Server 2003 and Exchange Server 2007 Exchange Hosted Services

Email Clients Providing access from anywhere Microsoft Office Outlook, Windows Mail and Entourage Outlook experience from desktop to web to mobile devices

Consumer and Small Business Windows Live Hotmail is the next generation of MSN Hotmail Office Live offering solutions to small business World-class protection and ease-of-use features

Corporate And Consumer Email Clients

Corporate Clients Consumer Clients

Services Transformation

Work Communicate Connect Live Play Word Processing Email Online Persona Photos & Video Casual Games Spreadsheets Instant Messaging Family/Intimates Music & Movies Action Games Presentations Internet Calling Friends Shopping Fantasy Games Documents Blogs Classmates Personal Interests Multiplayer Games News & Research Discussion Forums Affinity Groups News & Research Virtual Worlds

Hotmail History

Windows Live Hotmail

Powerful free e-mail, with security by Microsoft

Protected Productive Unified

Windows Live Hotmail now gives Windows Live Hotmail is Familiar, Windows Live Hotmail brings the you the control you need to keep Fast and Powerful helping you get power of desktop software to your e-mail private, safe, and more done anywhere on the web your personal webmail secure

Windows Live Hotmail – Ad UX

Display E-Mail

Optimizing E-Mail Deliverability Into Windows Live Hotmail: Part I

Brian Holdsworth Sr. Product Planner Microsoft Corporation

Spam Trends And Tactics First There Was Content Filtering, then Authentication

To combat reputation systems, spammers Spam Tactics increase distributed attacks And Volume Working around Content Filters 2-3X increase of spam past 12 months Spoofing and identity theft (phishing) grows rapidly Large increases of spam Shifting to illegal, illicit and high Wide range of products margin products Malicious payloads

Authentication + Main defense is content Authentication without reputation greatly 2005 2006 Reputation 2007 filtering and Block lists improves catch rate

Volume manageable Increases slowly over Users become aware of identity theft next 2 years Phishing and false positives biggest Senders with mixed or no reputation begin complaint having delivery problems Users become aware of Image spam and Spam In botnets Amidst new threats and volumes, spam in The Inbox the inbox continues to decrease

Windows Live Hotmail Trends Distributed or Short Lived Attacks

Spam volume up 40% since June 2006, 80% of increase from Botnet’s Bots send a lot of spam over a very short time period Botnet attacks involve a group of computers launching distributed attacks at the same time, not confined to a single IP range A single attack can be from 100k machines in over 100 different countries

Examples of short lived spam attacks

Total Email % Spam Length Volume (min) 1 2,800,000 98.5% 15 2 2,990,000 99.7% 22 3 4,800,000 99.0% 45 4 5,280,000 98.2% 47 5 1,950,000 98.5% 18

Windows Live Hotmail Trends Image-based Spam

33% of spam that Hotmail deletes has images 74% of images are one single image 17% at Exchange Hosted Filtering Examples of Image Spam

Windows Live Hotmail Trends Spam Business Has Changed Over Time

Example of selling trends over time Percent of email reported as spam by Windows Live Hotmail Users

Microsoft’s Anti-Spam Strategy Protect users from unwanted and fraudulent communications

Education and Prescriptive Guidance Industry and Business Collaboration Online and offline resources Industry Business and government Whitepapers and case studies partnerships Microsoft.com/security Legislation and enforcement Microsoft.com/safety 376 enforcement actions since inception of Internet Safety Enforcement team Postmaster.live.com Best practices, standards and policies

Innovative Technologies Investments Protecting 600M today - 1B by 2009 Sender Reputation Servers, services and clients sharing reputation data Consumer Corporate IP + URL + domain + user reputation Services Services Attack detection systems

Authentication + Identity Product Logos go here! Sender ID Framework Outlook Email Postmark Content Filtering Low cost machine learning algorithm (user driven) User Personalization Desk top Learn from user behavior and direct feedback Enterprise Clients Servers Graymail, email that is wanted by some, not others 21 © 2007 Microsoft Corporation.

Windows Live Hotmail Anti-Spam Technology

Average of 4.5+ Billion emails per day 90% classified as spam

IP Block Lists SmartScreen™ Spam / Phishing / Signatures

Sender ID Check Attack Detection and Computational Proof Updates Connection (Outlook Postmark) Check Filtering Sender Score Certified (Safelist provided by Return Path) Symantec Brightmail Reject Connections

Inbox User Based Filters and Lists Junk Delete

User Feedback SmartScreen ™ Patented Junk Mail Reports Machine Learning System Trap Accounts Rapid Response Analysis and Metrics

Windows Live Hotmail Anti-Spam Technology

What we’ve done to protect users and reduce spam in the inbox New simplified UI to add users to safelist, report junk, or warn about dangerous emails IP Throttling and block lists (reduce overall volume) Signatures, most content based spam

What we’ve done to improve deliverability for Legitimate Senders Volume based reputation data, IP safelist improvements Combine Sender ID and previous reputation Computation Proofs (Outlook Postmark) Unsubscribe option reduces user complaints

Remember, The Rules For Deliverability Have Changed

Chaf IP Reputation Can SPAM

Compromised Domain User Botnets PC’s Authentication Feedback

Phishing Brand Fraud ISP Policies Graymail

Image spam Mailing Lists

Unsubscribe

Past mailing behavior or patterns Reputation and authentication User feedback and unsubscribe opt-out Clean mailing lists - know who wants your mail and who doesn't Message header and content

Why Reputation Matters?

Impact to legitimate e-mail senders Content filtering alone causes unpredictable delivery behavior Not all content filters are created equal, without reputation content rules Reputation drives a large portion of e-mail delivery decisions End user experience Content Filters can be fooled, takes time to learn Authentication and Content Filtering feed into reputation systems

User Complaints Unknown Users Sending Infrastructure Spam Traps Bad Mailing Lists Patterns and Consistency

Why User Reputation Matters – Junk Mail Reports Email Classified as “Junk” by Windows Live Hotmail Users

Why User Reputation Matters Windows Live Hotmail Feedback Loop

Feedback Loop, what is it? Non-biased, opt-in user feedback Data used with JMR and other sources, input into SmartScreen technology How does it work? Email randomly selected and sent to user Previously deleted or delivered email User classifies as “junk” or “not junk” e-mail How are users selected? Random Multiple Languages Why is FBL important? Users active for 6 months Additional input into both reputation systems and SmartScreen filtering 10M participants Users in 233 countries Good trending indication of both legitimate 12 langs, 60% non-U.S email or spam

Why User Reputation Matters – FBL Reports Email Classified as “Not-Junk” by Feedback Loop Users

Ebay Transaction HTML + Newsletter Promotion

Winning Back Inactive Subscribers

Amazon Order Confirmation

Why User Reputation Matters Junk Email Options for Windows Live Hotmail Users

Known Sender User added sender to personal “safelist” or “contacts: Images and links enabled Allows unsubscribe option

Unknown Sender Sender not in user safelist or contacts User chooses “junk”, “delete” “mark as safe” or “unsafe”

Potentially Dangerous Could be phishing or sender ID failure (spoofed) User options same as unknown sender

Why User Reputation Matters Unsubscribe from Unwanted Mailing Lists

Helps users and legitimate email marketers Best practice developed with input from users and marketers Works for Windows Live Hotmail, not MSN Hotmail How does it work? Sender adds List Unsubscribe header (as specified in RFC 2369) Users adds sender to personal “safellist”, “contact list”, or be member of Sender Score Certified global safelist Allows user to tell senders “please remove me” from unwanted mailing lists Does this apply to all mail sent? Applies to email previously identified by users as wanted or legitimate

Why Authentication Matters - Sender ID Framework Authentication + Reputation = Identity

Sender Reputation User Feedback

Most anti-spam solutions use reputation and authentication to aid spam filters Authentication provides a “driver's license” for the sending domain a basis for reputation - SPF Text Record (DNS Zone file) Provides a way to tell if the “from line” in the email was spoofed Prevalent in phishing - PRA/Mail From Lookup Significantly improves deliverability of legitimate email Along with past sender reputation and user feedback 31 © 2007 Microsoft Corporation.

Personal Reputation - Identity Outlook 2007 Email Postmark

Problem Individual users mail may appear like spam to filters but are legitimate Improving deliverability & legitimacy, reducing the risk of being junked

Solution – Outlook Email Postmark Microsoft SmartScreen analyzes the mail for content that might trigger heuristics on receiving networks Outlook attaches a Postmark or computational puzzle on the mail before being sent, (takes 8-10 seconds of computing time), transparent to the user. Receiving networks validate the token and apply a score to the Spam Confidence Level (SCL)

Sender Best Practices Increase your chances for successful deliverability

Format a reply header to ensure subscribers see your "friendly" email address Use a consistent "from address" and your company's name in the subject line Add text to the top of emails asking subscribers to add you to their address book or specifically "mark as safe" By doing so future emails will have images and links will be enabled by default Keep mailing lists clean! Purge old, bad, or inactive addresses from your mailing lists Acquire names responsibly and send mail only to users that "opt-in” to receiving your email Add text reminding subscribers where they opted-in to receive your email Add "list unsubscribe" header offering subscribers a clean way to opt-out Honor unsubscribe requests! Opting out should be just as simple as opting-in Remove names responsibly without follow-up emails or extra steps. Choose content wisely Don’t look like a spammer Verify URLs are look normal and point to valid domains

Sender Best Practices Increase your chances for successful deliverability

Use a reputable email service provider who has relationships with ISP's such as AOL, Yahoo and Hotmail Be consistent – Send mail from same IP’s Use domain authentication – Sender ID Helps protect from spoofing and ensure your MTA is authorized to send mail Separate traffic by brand or type of mail Customer acquisition, customer retention and transactional should be separated Less is more! Send less mail more often vs. lots of mail for short periods of time Setup, monitor and proactively manage your user feedback data Feedback loops contain valuable spam complaint information Monitor and manage both hard and soft bounces. Bounce notices provide invaluable information regarding the ISP’s treatment of your mail

Sources Of Feedback

For ISPs The short list Monitor effectiveness of spam filtering Hotmail Postmaster Services Feed internal reputation systems Microsoft JMR Program Monitor outbound spam Microsoft SNDS

For Senders Blacklist reports Monitor brand and IP reputation Spamcop, Spamhaus Stay below complaint thresholds for good deliverability AOL and other ISP’s Adjust frequency and relevance of AOL scomp messaging AOL report card Identify problem

Deliverability Consultants For Deliverability Consultants Habeas Feed independent reputation aggregators Return Path Help senders fix deliverability problems Senderbase

Postmaster Services http://www.microsoft.com/postmaster or http://postmaster.live.com

Services and self-help documentation to help improve email deliverability and reduce outbound spam Junk Email Reporting Program (JMR) - Info [email protected] Instant feedback on user complaints for list maintenance & daily reporting Tailored to large senders remove recipients from their lists. Senders receive any mail that is reported as junk mail. Smart Network Data Services At a glance deliverability reports Measures of outbound traffic and complaints from your IP space Isolate compromised hosts/servers Sender ID information Support Information including FAQ’s and escalation options

Smart Network Data Services What is Smart Network Data Services? Provides data that empowers service providers to track spam originating from within their IP space Provides data to empower senders to track reputation Expected Use Detect unexpected or suspicious mail activity – spammers, botnets, malware Improve reputation of your sending domains What will you get? Mail traffic data Data representing factual information about email sent from your IP space to Hotmail Activity over SMTP, verb and message recipient counts, and sample commands Junk mail data Filter results, complaint reports, spam trap hits, virus reports, open proxy status Who’s using it? 10k+ unique users with over 150M authorized IPs Represents 48% of mail sent to Hotmail Access http://postmaster.live.com/snds

Smart Network Data Services Example

Future: Anti-Spam Roadmap Continued Investments In The Following Areas:

Content Filtering Continued orthogonal protection Improve with more reputation sources Centralized and distributed reputation Consumer Corporate Servers, services and clients sharing Services Services central reputation data Broad data sources and detection: IP + URL + domain + user reputation Product Logos go here! Low latency Shared Central Authentication Reputation System Sender ID Framework Continues to supplement reputation and content filtering Desk top Personalization Enterprise Clients Servers Learn from user behavior Direct and indirect feedback Key to opt-in email (graymail) wanted by some and spam to others

Things to Remember

Senders Authentication ALL outbound email Manage your reputation – on your own or with help from others Follow sender best practices – good clean mailing lists, unsubscribe, quality content

IT Infrastructure and ISP’s Authentication both inbound and outbound email Aggregate IP reputation to authenticated domain Use authentication + reputation in your filtering decisions Use SNDS, find out who is sending email from your IP space

Optimizing E-Mail Deliverability Into Windows Live Hotmail: Part II

Kelly Sieben Escalation Policy Manager Microsoft Corporation

Complaint Prevention Privacy And Reputation Are Tied At The HIP

Notice – Manage registration process to Give subscribers a positive choice meet future expectations Give them a good idea of what they will receive Give instructions on address book inclusion

Consent – Use the highest permission Best: Double opt-in; Low bar: Confirmed opt-in Advantages: Fewer unsubscribes, Fewer complaints, standard you can support Better Reputation, Better Deliverability Choice – Give them options Make opt-in choices granular Newsletters, Brands, Frequency, Partner Offers Show them examples

Frequency and Relevancy – Message Send a welcome message Ensure appropriate mail frequency /avoid content and program relevancy impacts subscriber fatigue behavior Stay consistent Use customization and personalization Target messaging

Opt-Out – always respect unsub requests Make it easy to unsubscribe Make sure it works Global and granular choices Ensure CAN-SPAM and EU/AU compliance

Complaint Prevention Notice: Show New Subscribers What To Expect

Manage your customers Expectation versus Experience What will they get? How often will they get it? Who will it come from? What will it look like? Provide an example.

Complaint Prevention Choices: Give Users Options

Messages (Newsletters, Featured Offers, Promotional, etc..) Brands Addresses (Which one/ones)? Formats Timing Prospects/Third Party Lists

Complaint Prevention Set Boundaries For Transactional Email Privacy Implications: Transactional Emails are “NOT” covered but…dual purpose e-mail MAY be covered under proposed FTC rules if: Subject line focused on commercial/promotion messages Content can be “reasonably interpreted” as being “primarily” advertising Factors to watch: Placement of the commercial message at the top of the message Advertisement is clearly in higher proportion to other types of content (information or transactional information) Graphical weight (type size, font, colors, etc) Recommendation: Consider use dedicated IP(s) Target and Test Up sell footer Monitor Complaints

Complaint Prevention Set Boundaries for Peer-To-Peer/Viral Marketing Privacy Implications: CAN SPAM “may” apply depending on who the sender is and is the service is being promoted. “E-mail to a friend” - the web site operator is not the “sender” of the forwarded message. “Tell-A-Friend…Help spread the word by forwarding this message to friends!” - the web site operator becomes the sender of the forwarded message, and assumes all the corresponding obligations. Reputation Impacts: User account abuse and phishing concerns Negative PR

“The social networking site … is requesting their users' AOL, Gmail, Yahoo and Hotmail passwords, and then using them to access users' address books and send 'invitations' to join …. making them appear to come from the user. The password prompt screen includes the ISP's logo right next to the password prompt. Rather than hiding this little 'feature,' … “ / “…. does they same. They ask for your e-mail address and e-mail address password, then spam your contact list. I can't believe people will give them their password, but some actually do. Preposterous!”

“One new social networking site is a poster child for the abuse of social networking...when a user signs up…they're practically forced to put in their Webmail credentials. ….then logs into your Webmail account as you, accesses your address book and prompts you to e-mail your contacts using your Webmail address as the reply-to." Sources: Slashdot “Deceptive Viral Practices? “ Monday March 26 and eWeek.com “Harvesting Teenagers: “ By Larry Seltzer April 10, 2007

Complaint Prevention Set Boundaries for Peer-To-Peer/Viral Marketing Recommendations: Get Permission Provide users with communication choices Provide Clear Notice Don’t ask for users passwords Use Windows Live Contacts Control Client Side tool that enables users to share their Windows Live Contacts with your site in a safe and secure way.

http://dev.live.com/contactscontrol/v0.2/default.aspx

Windows Live Hotmail Optimizing the Inbox

Known Sender User added sender to personal “safelist” or “contacts: Images & links enabled Allows unsubscribe option

Unknown Sender Sender not in user safelist or contacts User chooses “junk”, “delete” “mark as safe” or “unsafe”

Potentially Dangerous Could be phishing or sender ID failure (spoofed) User options same as unknown sender

Windows Live Hotmail Optimizing the Inbox Ideal Scenario Publishing Sender ID Known Sender (Marked as Safe/In Contact List) Images and Links enabled for all messages Publishing Unsubscribe Helps reduce complaints

Outlook 2007 Optimizing the Inbox Best Practices: Do not use background images Do not use CSS (cascading style sheets) Inline style attributes are your only option Use only basic HTML tags (For instance, to underline text, use the tag, for bold use the tag.) If you’re developing content in Dreamweaver, be sure to use the validation schema for Microsoft Word 2007

More Info: Outlook 2007’s HTML capabilities http://msdn2.microsoft.com/en-us/library/aa338201.aspx Outlook 2007 Content Compatibility Tool http://www.microsoft.com/downloads/details.aspx?familyid=0b764c08-0f86-431e-8bd5- ef0e9ce26a3a&displaylang=en

Microsoft Phishing Filter

Dynamic protection against fraudulent websites Built-in Vista/IE7 and Windows Live Toolbar 3 “checks” to protect users from phishing  Compares web site with local list of known legitimate sites  Scans the site for characteristics common to phishing sites  Double checks site with online Microsoft service of reported phishing sites dynamically updated

Two Levels of Warning and Protection in IE7 Security Status Bar

Microsoft Phishing Filter Prevention of “False Warnings” a Key Goal

Built-In Online Reporting for Individuals and Website owners Website owner submits a request Microsoft will examine the request and have a human grader make a determination on the site Aggressive turnaround time for each request Website owner gets confirmation e-mail after request is examined

Outlook 2007 Don't look like a Phisher

Windows Live Hotmail Don't look like a Phisher

Phishing Do’s And Don’ts

E-mail Content Web Content

Authenticate - SenderID Certify – SSL (Trusted Authority) Domain - Use consistent naming Protect - Prevent XXS Vulnerabilities conventions (it’s your Brand) Domain - Use a fully-qualified domain Avoid requests for personal name information Don’t use the @ symbol Avoid live links in Billing Don't encode or tunnel your URLs Communications Avoid alarmist messaging Make it personal and professional

Phishing Filter FAQ: https://phishingfilter.microsoft.com/faq.aspx

Deliverability - Top Support Drivers

Postmaster Tools General Deliverability Policy Based IP Blocks Sender ID Content Filtering Brightmail Other

Deliverability Troubleshooting “Whitepaper” Preview

Scenario 1: Your inbound e-mail to MSN Hotmail or Windows Live Mail users is not being delivered as expected.

Symptoms 1. Your e-mail appears to be getting blocked by MSN Hotmail or Windows Live Mail. 2. Your e-mail is being delivered to recipients’ Junk E-Mail Folders (JMF). 3. Your e-mail is bouncing or you can’t connect

Common Causes Recommended Actions Server Properly configure anti-virus software on your firewall or your SMTP Gateway Configuration Configure your Domain Name Server (“DNS”) server correctly Enable Reverse DNS Lookup Be aware of MSN Hotmail and Windows Live Mail Volume Caps Insure your outbound mail is Sender MSN Hotmail and Sign-up for JMRP Check the age of your user lists Windows Live Mail Use Double Opt In when customers sign up to receive your e-mails Complaint Rate Make the Unsubscribe option easy to find and that you honor all requests Monitor the frequency of your e-mail. Ask customers for feedback. Are customers receiving what they originally signed up for? Microsoft Block list If you believe your e-mail has been blocked by Microsoft check third party blacklists Contact Support

Deliverability Issues? Windows Live Mail Support Options

Step 1 - Ensure Compliance - Make sure you are in compliance with Windows Live Policies and Technical Requirements http://postmaster.live.com/Guidelines.aspx Step 2 - Follow best practices and FAQ’s http://postmaster.live.com/troubleshooting http://www.microsoft.com/postmaster read FAQ’s and Improving Deliverability whitepaper* Step 3 - Adopt SenderID and Keep Your Record Current Microsoft.com/safety & Microsoft.com/SenderID Step 4 – Join the Junk Mail Reporting Program http://support.msn.com/default.aspx?productkey=edfsjmrpp&mkt=en-us Step 5 – Leverage Smart Network Data Services (SNDS) https://postmaster.live.com/snds/index.aspx Step 6 – Contact Deliverability Support - If you’re doing all of the above. http://support.msn.com/eform.aspx?productKey=edfsmsbl&mkt=en-us

Deliverability and Reputation Consulting Services: Acxiom Media , Datran Media, Epsilon, Habeas, Return Path, TRUSTe, etc… Members of www.espcoalition.org

Windows Live Hotmail Deliverability Optimization Summary

Complaints Drive Reputation – prevent them! Notice/Relevancy – Ensure you users know your mail and expect it Optimize the UI User Safelist – Get users to mark you mail as safe / add your address to their contact list Publish Unsubscribe Don’t look like a Phisher Monitor via SNDS Join the JMRP Complaint Issues – Make sure you are doing all the above and do analysis

For more informaiton

Postmaster Services www.microsoft.com/postmaster JMR & SNDS http://postmaster.live.com Sender ID www.microsoft.com/senderid AOTA www.aotalliance.org

How Sender ID Works

SPF Examples

SPF Record Description example.com TXT “v=spf1 -all” This domain never sends mail Can also protect sub domains example.com TXT “v=spf1 mx -all” Inbound email servers also send outbound mail

example.com TXT “v=spf1 Mail originates from a specific IP ip4:192.0.2.0/24 -all” address range

example.com TXT “v=spf1 mx Outbound email service provider is include:myesp.com ~all” included as an authorized sender

example.com TXT “spf2.0/pra Explicit SPF record for PRA check ip4:192.0.3.0/24 ?all”

• Refer to RFC4408 for complete details

SPF Record Syntax

SPF Mechanism Description ip4 Explicitly specify a single IP v4 address or CIDR range mx Refer to the MX records of the sending domain or any other domain Recommend including “mx” since most inbound servers also send DSNs a Refer to the A records of the sending domain or any other domain include Refer to the SPF records of another domain For outsourced email service providers For referring to IP addresses shared by multiple divisions For splitting up large SPF records into smaller components

ptr Refer to PTR records (reverse DNS) of sending IP Discouraged due to DNS overhead all Default when all other mechanisms fail to match

Common SPF Problems

1. Wrong version string for spf2.0 records

Incorrect Correct “v=spf2.0 ….” “spf2.0 …”

2. Use of “mx” for a mail host Incorrect Correct “v=spf1 … mx:mail1.example.com …” “v=spf1 … a:mail1.example.com ….”

3. Redundant use of “mx” for same domain

Incorrect Correct “v=spf1 a mx ip4:10.1.2.3/24 “v=spf1 a mx ip4:10.1.2.3/24 …” mx:example.com …”

Common SPF Problems

4. Including a non-existent SPF record

Incorrect Correct “v=spf1 … include:nospf.com …” “v=spf1 … include:myesp.com …”

5. Incorrect redirect Incorrect Correct “v=spf1 … redirect:contoso.com” “v=spf1 … redirect=contoso.com”

6. Use of “+all” Incorrect Correct “v=spf1 … +all” “v=spf1 … -all” or “v=spf1 … ~all”