ExchangeDefender PTR & RBL Whitelisting | ExchangeDefender [ Skip to content ](#main) [ ![ExchangeDefender](/assets/images/xd_logo_blue.png) ](/) Email Security ![Platform Overview](/assets/images/m-xd-pro.png)### ExchangeDefender PRO Enterprise-grade email security made simple for every business. [Sign Up](/sign-up) [Live Demo](/demo) [Email Security Stops spam, malware & phishing in real time. ](/email-security) [Encryption Secure your emails, attachments & sensitive data. ](/corporate-email-encryption) [Web File Sharing Easy, safe cloud file sharing with access control. ](/web-file-server) [Live Archive Locked-in email backup & continuity during outages. ](/livearchive-backup) [Emergency Inbox Keep email flowing without interruption if your provider fails. ](/inbox) [Spearphish Train your team with phishing simulations & risk tracking. ](/spearphishing) Managed Email ### Enterprise-Grade Managed Email Reliable, secure, and fully managed email operations for modern organizations. ![ExchangeDefender](/assets/images/managed_email_menu.png) [Microsoft365/Google Email Management Expert management and security for Microsoft 365 and Google Workspace email. ](/managed-email-operations) [AI Advisory Secure, practical AI consulting & implementation for SMBs. ](/management-ai) Company ### ExchangeDefender: 29+ Years of Trust We are a cybersecurity company focused on business email protection, with 29+ years of experience keeping organizations secure, connected, and resilient. ![ExchangeDefender](/assets/images/careers_1.png) [ About Us Learn our purpose, values, and the mission behind every decision. ](/about-us) [ Blog News, product updates and email security insights. ](/blog) [ Capabilities Discover the tech and expertise that keep your email secure around the clock ](/capabilities) [ Careers Be part of a team using modern tech to solve real threats and ship great work. ](/careers) [Partners](/partners) [Docs](/docs) [Contact Us](/contact) Talk to a Human Open menu Menu ---- Email Security [Email Security](/email-security) [Encryption](/corporate-email-encryption) [Web File Sharing](/web-file-server) [Live Archive](/livearchive-backup) [Inbox](/inbox) [Spearphish](/spearphishing) Managed Email [Microsoft365/Google Email Management](/managed-email-operations) [AI Advisory](/management-ai) Company [About Us](/about-us) [Blog](/blog) [Capabilities](/capabilities) [Careers](/careers) [Partners](/partners) [Docs](/docs) [Contact Us](/contact) Talk to a Human May 9, 2019 · [General](https://www-preview.exchangedefender.com/blog?category=uncategorized) ExchangeDefender PTR & RBL Whitelisting =========================================== ![](https://storage.services.exchangedefender.network/exchangedefender-blog/blog/2019/05/Whitelist.jpg) ExchangeDefender is opening a wider beta test of our whitelisting functionality, which allows IT Solution Providers to whitelist sender mail servers that have broken DNS (missing PTR, mismatched A/PTR records) and poor sender reputation (hosts listed on multiple RBL blacklists). If you have a sender you would like to whitelist against these essential network tests, please open a ticket at support.ownwebnow.com with subject “Whitelist PTR/RBL: IP Address” and provide as much information in the ticket so we can accommodate this specific request. Only hard non-negotiable rejections to whitelist will be for unknown address space and dialup/consumer cable IP addresses (because due to their nature those are typically dynamically assigned address spaces that shouldn’t be relaying mail at all, they should be using their ISP mail server provided smarthost) ### Requests will be reviewed and either approved (and enrolled) or rejected within 24 hours by our CSO. Background: Inability to previously whitelist broken DNS and dynamic IP address space is rooted in our mission statement. We are here, beyond everything else, to help secure the email. We know our partners, IT Solution Providers, VARs, MSPs, etc do not have the skill set, the time to properly research underlying issues, enough data and statistical models to evaluate sender IP reputation, or even the incentive to discern how big of a security threat and compromise a specific IP address with broken DNS or poor reputation may pose to your client. In fact, you pay us to worry about those things and keep your clients secure. But, sometimes clients like to think they know better than their technology experts, generally accepted security standards on the Internet, and ExchangeDefender. And the client is always right. But, when they get infected attachments, broadcast storm, password dumps, or other security compromises because they insisted on lowering their security – then ExchangeDefender is on the hook for securing them. And we don’t get to say “told you so” nor do we have any rapid means to fix the issue. Since my retirement, all of those hard-line policies designed to keep clients safe beyond whatever “specific business case requirement” they may have, are slowly going away. *Good news for the client, good news for the partners.* Good news for us, because going forward we will start providing Email Security Engineering services – so when you get a security compromise or an usual issue and you’ve asked us to compromise your security – we will be able to address the issue on your behalf. I choose to look at this as a positive – we will help our clients meet their business needs and get the mail they desperately need – and if something breaks we will be there to help assist with the cleanup (for a fee, of course). This, among many other service related things, is just the part of the ExchangeDefender being more responsive and service oriented when it comes to our clients demands as opposed to our expert opinion as a security policy. ![](https://storage.services.exchangedefender.network/exchangedefender-blog/blog/2019/05/Copy-of-Copy-of-How-to-Pack-Light-1024x402.png)Sign up for the Webinar, **[click here](https://register.gotowebinar.com/register/2664310586691097091)**! [ Previous post ExchangeDefender's AnythingDown.com - See How It Works! April 26, 2019 ](https://www-preview.exchangedefender.com/blog/2019/04/exchangedefenders-anythingdown-com-see-how-it-works) [ Next post Sharing files with ExchangeDefender WFS May 21, 2019 ](https://www-preview.exchangedefender.com/blog/2019/05/sharing-files-with-exchangedefender-wfs) Related Posts ------------- [ 1 May ](https://www-preview.exchangedefender.com/blog/2026/05/exchangedefender-new-ui-is-live)### [ExchangeDefender New UI is Live](https://www-preview.exchangedefender.com/blog/2026/05/exchangedefender-new-ui-is-live) [Read more: ExchangeDefender New UI is Live](https://www-preview.exchangedefender.com/blog/2026/05/exchangedefender-new-ui-is-live) [ ![](https://storage.services.exchangedefender.network/exchangedefender-blog/blog/2026/04/xd10.png) 2 Apr ](https://www-preview.exchangedefender.com/blog/2026/04/announcing-exchangedefender-10)### [Announcing ExchangeDefender 10](https://www-preview.exchangedefender.com/blog/2026/04/announcing-exchangedefender-10) [Read more: Announcing ExchangeDefender 10](https://www-preview.exchangedefender.com/blog/2026/04/announcing-exchangedefender-10) [ ![](https://storage.services.exchangedefender.network/exchangedefender-blog/blog/2025/12/christmas-1.jpg) 25 Dec ](https://www-preview.exchangedefender.com/blog/2025/12/merry-christmas)### [Merry Christmas](https://www-preview.exchangedefender.com/blog/2025/12/merry-christmas) [Read more: Merry Christmas](https://www-preview.exchangedefender.com/blog/2025/12/merry-christmas) Search the blog Search Recent Posts ------------ - [ExchangeDefender New UI is Live](https://www-preview.exchangedefender.com/blog/2026/05/exchangedefender-new-ui-is-live) - [Announcing ExchangeDefender 10](https://www-preview.exchangedefender.com/blog/2026/04/announcing-exchangedefender-10) - [Merry Christmas](https://www-preview.exchangedefender.com/blog/2025/12/merry-christmas) - [Why IoT Devices Are a Hidden Security Risk for Your Business](https://www-preview.exchangedefender.com/blog/2025/11/why-iot-devices-are-a-hidden-security-risk-for-your-business) - [Top 5 IT Problems Small Businesses Face in 2025 — and How to Fix Them](https://www-preview.exchangedefender.com/blog/2025/10/top-5-it-problems-small-businesses-face-in-2025-and-how-to-fix-them) Categories ---------- - [Archiving](https://www-preview.exchangedefender.com/blog?category=archiving) (21) - [Business Continuity](https://www-preview.exchangedefender.com/blog?category=business-continuity) (13) - [Compliance](https://www-preview.exchangedefender.com/blog?category=compliance) (8) - [ExchangeDefender](https://www-preview.exchangedefender.com/blog?category=exchangedefender) (349) - [General](https://www-preview.exchangedefender.com/blog?category=uncategorized) (590) - [Hosted Services](https://www-preview.exchangedefender.com/blog?category=hosted-services) (86) - [Industry News](https://www-preview.exchangedefender.com/blog?category=industrynews) (29) - [Marketing](https://www-preview.exchangedefender.com/blog?category=marketing) (18) - [Phishing](https://www-preview.exchangedefender.com/blog?category=phishing) (5) - [PRO TIPS](https://www-preview.exchangedefender.com/blog?category=pro-tips) (44) - [Product Features](https://www-preview.exchangedefender.com/blog?category=product-features) (54) - [Security](https://www-preview.exchangedefender.com/blog?category=security) (65) - [Shockey Monkey](https://www-preview.exchangedefender.com/blog?category=shockey-monkey) (22) - [Spamfilter](https://www-preview.exchangedefender.com/blog?category=spamfilter) (5) - [Support](https://www-preview.exchangedefender.com/blog?category=support) (45) - [Webinars](https://www-preview.exchangedefender.com/blog?category=webinars) (44) Solutions --------- - [Stop Spam & Malware](/email-security) - [Hands-Free Email Backup](/livearchive-backup) - [Instant Email Recovery](/inbox) - [Send Private Emails](/corporate-email-encryption) - [Train Against Email Threats](/spearphishing) - [Share Files Safely](/web-file-server) Company ------- - [About ExchangeDefender](/about-us) - [Compliance & Legal](/our-compliance) - [Become a Partner](/partners) - [Support Portal Login](https://support.exchangedefender.com/) - [Microsoft 365 Email Management](/managed-email-operations) - [AI Advisory Service](/management-ai) ![ExchangeDefender](/assets/images/dark-xd-logo.png)USA: +1 (407) 465-6800 United Kingdom: 0800 8620149 Australia: +61 0390010641 Fax: +1 (954) 839-8737 [ ](https://www.facebook.com/ExchangeDefender) [ ](https://www.twitter.com/XD_Defender) [ ](https://www.linkedin.com/company/exchangdefender) [ ](/blog) © 2026 Own Web Now Corp - All rights reserved </> with ❤️ in Orlando [SLA](/sla) [TOS](/tos) [PRIVACY](/privacy-end-users) [AUP](/aup) We're Here to Help 👋 -------------------- Tired of AI 🤖 and hold music? 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