ExchangeDefender Delivery Alert | 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. 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At this point we have been able to narrow it down to Microsoft Exchange 2003 servers running IMF v2 and Microsoft Exchange 2007 servers also running IMF. In all instances the mail was acknowledged by ExchangeDefender, processed and delivered to the target mail server. In several instances mail disappeared completely. In others only certain recipients *"didn't get"* the message. > **We cannot stress this strongly enough: Turn OFF any SPAM filtering enabled on your servers, along with any SPF checking, validation or firewall port 25 data inspections.** The only rules that should be enabled are those described in previous posts dealing with port 25 restrictions. **How come an email was received by one user but not on the other if they were cc'ed?** Frequent question asked today in our support portal. For example, two users in the same organization were receiving an email. Or perhaps a distribution list where a single email address delivers to Outlook/mbox and other relays externally to a Blackberry address. If one gets it and the other doesn't thats ExchangeDefender's fault, no? No. ExchangeDefender does not modify/alter the message body nor does it split the message that is being delivered. The message is delivered in a single direct stream at which point Exchange further processes the message and delivers it to the delivery agent (which further relays the message or forwards it depending on local rules.) Exchange also uses technology called *single instance storage*, allowing a single message to be stored in the database if it is received for multiple recipients. So, if a message was received by one user it must have been received by the other. Why can one see it while the other can't? Turn up message tracking and see. However, we are currently seeing this as an issue related to Outlook Junk Filters and IMF, both of which need to be disabled for reliable mail delivery. [ Previous post ExchangeDefender activates the new IP range August 14, 2007 ](https://www-preview.exchangedefender.com/blog/2007/08/exchangedefender-activates-the-new-ip-range) [ Next post End of an era at ExchangeDefender August 16, 2007 ](https://www-preview.exchangedefender.com/blog/2007/08/end-of-an-era-at-exchangedefender) 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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