Summary
Delivering emails to government (.gov) and military (.mil) accounts presents unique and significant challenges due to their extremely high security protocols and aggressive filtering mechanisms. Federal agencies are mandated to enforce robust email authentication standards like SPF, DKIM, and DMARC, making perfect alignment crucial for deliverability. While all government domains are highly restrictive, .mil addresses are exceptionally difficult, often requiring senders to suppress them entirely due to strict Department of Defense policies that even break links and limit communication from non-.mil domains. For all government targets, maintaining a pristine sender reputation, meticulous list hygiene, and often direct whitelisting efforts are paramount, as standard email best practices alone are frequently insufficient to bypass their sophisticated security gateways.
Key findings
- Extreme Security: Government and military email systems operate under exceptionally high security postures, driven by federal mandates (CISA, NIST) and a constant threat landscape, leading to aggressive spam and security filtering.
- Strict Authentication Mandates: Federal agencies are required to implement and enforce email authentication protocols, specifically SPF, DKIM, and DMARC, making impeccable authentication non-negotiable for deliverability to .gov and .mil domains.
- .mil Specific Challenges: Bulk marketing messages rarely reach .mil inboxes due to Department of Defense policies against communication from non-.mil domains; links are often broken, and suppressing these addresses is a common, sometimes legally advised, practice.
- .gov Filtering Mechanics: Many .gov domains utilize scoring systems like SenderBase (Talos Intelligence), often requiring a very high sender score (e.g., above 80/100) to bypass their filters, even if generally rated "Good."
- Content Adaptation: High-level government agencies frequently prefer or only render plain text emails due to security concerns associated with HTML content.
Key considerations
- Perfect Email Authentication: Ensure impeccable SPF, DKIM, and DMARC setup and alignment for all outgoing mail, as this is a fundamental requirement for bypassing government email filters.
- Pristine Sender Reputation: Meticulously manage sender reputation by avoiding spam complaints, maintaining consistent sending volume, and staying off blacklists, as government domains have zero tolerance for poor standing.
- Meticulous List Hygiene: Regularly validate email lists, implement double opt-in, send only to highly engaged and explicitly opted-in recipients, and promptly honor unsubscribe requests to minimize bounce rates and maintain deliverability.
- Pursue Direct Whitelisting: Proactively communicate with government IT departments to request whitelisting of your sending domain or IP address, as this is often the most effective way to bypass highly restrictive gateways for critical communications.
- Adapt Content and Format: Prioritize sending plain text emails, avoid URL shorteners, and ensure content is highly relevant, free of suspicious links or attachments, and not spammy, to align with the stringent security policies of government systems.
What email marketers say
12 marketer opinions
Email deliverability to government and military accounts remains exceptionally challenging, stemming from their mandate for extreme security and highly aggressive filtering. While perfect SPF, DKIM, and DMARC authentication is a non-negotiable baseline, senders must recognize that standard deliverability practices are often insufficient. Department of Defense policies can render .mil addresses virtually unreachable for bulk messages and even one-to-one communications from non-.mil domains, sometimes breaking links directly. For both .gov and .mil, success often hinges on transcending automated filters by achieving pristine sender reputation, rigorously managing recipient lists, adapting content to plain text preferences, and proactively engaging with agency IT for direct whitelisting, as some issues are simply unfixable by the sender.
Key opinions
- Unfixable Policy Barriers: Some deliverability issues, particularly with .mil addresses, are unfixable due to Department of Defense policies that actively break links and restrict communication from non-.mil domains, even for one-to-one emails.
- Beyond General 'Good' Ratings: Even if a sender's IP or domain is generally rated 'Good' by systems like SenderBase (Talos Intelligence), deliverability to .gov domains can still fail if the score does not meet a specific agency's higher threshold, often above 80/100.
- IT Gatekeepers & Whitelisting: Government IT departments frequently act as strict gatekeepers, making direct communication and proactive whitelisting requests essential, as standard email deliverability practices are often insufficient to bypass their highly restrictive filters.
- Sophisticated Security Layers: Government and military domains employ highly sophisticated email security solutions, including aggressive spam filters, that perform rigorous checks, making deliverability contingent on more than just basic compliance.
Key considerations
- Prioritize Direct IT Engagement: Beyond standard best practices, proactively communicate with government IT departments to understand specific policies and to seek direct whitelisting of your sending domain or IP, as this is often critical for bypassing restrictive gateways.
- Strategic Exclusion of .mil: Given the stringent and often unfixable Department of Defense policies, consider suppressing .mil email addresses for bulk marketing to avoid wasted effort and potential reputation issues, as even one-to-one messages from non-.mil domains can be blocked.
- Ensure Consistent IP Use: Maintain a consistent sending IP address to build and sustain a reliable sender reputation, which is highly scrutinized by government and military email systems.
- Embrace Plain Text Communications: Favor sending plain text emails to government accounts, as many high-level agencies will not render HTML due to security risks, ensuring your message is seen as intended.
Marketer view
Marketer from Email Geeks explains that some issues with government email deliverability cannot be fixed, citing a DoD policy that breaks links to prevent malware and emphasizes the need to be aware of specific government policies.
17 Jan 2025 - Email Geeks
Marketer view
Marketer from Email Geeks explains that bulk marketing messages rarely reach .mil inboxes due to a DoD policy against communication with non-.mil domains, even for one-to-one emails. He recommends suppressing .mil emails, noting that IT teams often act as gatekeepers and his experience is primarily with .mil, not state .gov, domains.
8 May 2025 - Email Geeks
What the experts say
3 expert opinions
Email deliverability to government and .mil accounts remains exceptionally challenging, stemming from their mandate for extreme security and highly aggressive filtering. While perfect SPF, DKIM, and DMARC authentication is a non-negotiable baseline, senders must recognize that standard deliverability practices are often insufficient. Department of Defense policies can render .mil addresses virtually unreachable for bulk messages and even one-to-one communications from non-.mil domains, sometimes breaking links directly. For both .gov and .mil, success often hinges on transcending automated filters by achieving pristine sender reputation, rigorously managing recipient lists, adapting content to plain text preferences, and proactively engaging with agency IT for direct whitelisting, as some issues are simply unfixable by the sender.
Key opinions
- .mil Suppression Confirmed: Suppressing .mil email accounts is a real and sometimes legally advised practice, with instances of Email Service Providers doing so at the direct request of military legal personnel due to insurmountable policy barriers.
- Highly Restrictive Environments: Government and military email networks operate behind highly restrictive firewalls and employ sophisticated security gateways, demanding meticulous attention to every aspect of email deliverability.
- Authentication & Reputation Are Baselines: Correct DNS records, including SPF, DKIM, and DMARC, along with an exceptionally high sender reputation and a valid reverse DNS, are fundamental prerequisites for reaching these secure inboxes.
- Content & IP Best Practices are Crucial: Avoiding URL shorteners, maintaining clean and relevant content, and using dedicated IP addresses are crucial practices to navigate the aggressive filtering mechanisms of government and military email systems.
- Whitelisting Often Necessary: Direct whitelisting is frequently required to ensure deliverability, especially for .mil domains and contractors, as standard best practices alone may not be sufficient to bypass heavy filtering from systems like DISA, McAfee SMG, and IronPort.
Key considerations
- Master Core Deliverability: Ensure all fundamental email authentication, including SPF, DKIM, and DMARC, is perfectly configured. Also, confirm a valid reverse DNS and that your IP address and domain are not blacklisted, as these are non-negotiable baselines for government networks.
- Rigorous List Management: Maintain exceptionally clean mailing lists by sending only to highly engaged, explicitly opted-in recipients. This minimizes bounces and complaints, which are heavily penalized by secure government systems.
- Strategic Content Design: Avoid using URL shorteners, ensure all email content is clean, highly relevant, and free of suspicious links or attachments. Consider prioritizing plain text over HTML for critical communications due to security preferences.
- Proactive Whitelisting Efforts: Actively pursue whitelisting of your sending domain or IP address by directly communicating with government IT departments or military legal personnel. This is often the most effective method to bypass highly restrictive security gateways like DISA, McAfee SMG, and IronPort.
- Evaluate .mil Suppression: Given the extreme and sometimes unfixable policy barriers, including direct requests from military legal personnel, seriously evaluate whether suppressing .mil email addresses for bulk or even certain one-to-one campaigns is a necessary strategy for your sending program.
Expert view
Expert from Email Geeks confirms that suppressing .mil accounts is a real practice, citing an instance where a previous ESP he worked at suppressed them after a direct request from military legal personnel.
11 Oct 2024 - Email Geeks
Expert view
Expert from Spam Resource explains that sending email to government and .mil accounts requires careful attention due to highly restrictive firewalls. Best practices include ensuring correct DNS records (SPF, DKIM, DMARC), using dedicated IPs, avoiding URL shorteners, and maintaining clean content. For .mil domains, whitelisting is often necessary, and some DoD networks use DISA for heavy filtering, suggesting the need for extremely high sender reputation or direct IP connections.
5 Mar 2024 - Spam Resource
What the documentation says
3 technical articles
Delivering emails to government and .mil accounts is exceptionally challenging due to strict federal mandates for email security, including CISA and NIST guidelines. These directives require agencies to implement robust authentication (SPF, DKIM, DMARC), encryption, and threat detection, driven by a persistent threat landscape of phishing attacks. Consequently, emails lacking impeccable authentication or failing to adhere to stringent content and sender reputation standards are highly likely to be rejected or quarantined, underscoring the critical need for senders to meet these elevated security requirements.
Key findings
- Mandatory Federal Authentication: CISA.gov explicitly mandates that federal agencies implement and enforce DMARC, SPF, and DKIM to enhance email security, making these non-negotiable for senders.
- Rejection for Auth Failure: Emails failing DMARC, SPF, or DKIM authentication checks are highly likely to be rejected or quarantined by government and .mil email systems due to these mandates.
- Threat-Driven Security Posture: Government and military email systems maintain an extremely high security posture, driven by ongoing phishing campaigns and the need for robust threat detection, leading to aggressive filtering.
- NIST Compliance Impact: NIST Special Publications, such as SP 800-53, outline comprehensive security and privacy controls for federal information systems, which directly necessitate stringent email security measures for deliverability.
Key considerations
- Perfect Authentication Required: Ensure impeccable SPF, DKIM, and DMARC alignment for all outgoing mail, as these are federal mandates and a fundamental requirement for bypassing government email filters.
- Zero Tolerance for Reputation Issues: Meticulously manage sender reputation, as government and military systems have an extremely high security posture and aggressive filters that will reject mail from any questionable senders.
- Stringent Content & Hygiene: Adhere to the highest standards of content and list hygiene, ensuring emails are free of any elements that could trigger advanced security filters mandated by federal guidelines like NIST.
- Adherence to Federal Security Protocols: Beyond basic deliverability, understand that you must meet comprehensive federal security standards, including strong authentication, encryption, and threat detection, to reach these secure inboxes.
Technical article
Documentation from CISA.gov explains that federal agencies are mandated to implement DMARC, SPF, and DKIM to enhance email security. This directive significantly impacts deliverability to .gov accounts, as emails failing these authentication checks are likely to be rejected or quarantined, emphasizing the critical need for senders to properly authenticate their outgoing mail.
11 Jul 2023 - CISA.gov
Technical article
Documentation from CISA.gov highlights multiple phishing campaigns targeting government organizations. This ongoing threat landscape necessitates an extremely high security posture for .gov and .mil email systems, emphasizing the need for senders to ensure perfect authentication (SPF, DKIM, DMARC) and maintain a clean sender reputation to avoid being flagged by their aggressive filtering mechanisms.
18 Aug 2022 - CISA.gov
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