Summary
Domain blocking in specific countries presents a complex challenge to email deliverability and image rendering. While direct deliverability to other regions might not be immediately affected, several factors can lead to negative consequences. DNS-level blocks disrupt authentication protocols (SPF, DKIM, DMARC), leading to delivery failures, spam classifications, or quarantines. Image rendering is compromised if images are hosted on subdomains of the blocked domain or served through blocked CDNs. Reduced engagement and increased complaints from blocked regions can indirectly harm sender reputation. Legal/policy reasons behind the blocks necessitate respecting regional restrictions. Mitigation strategies include robust DNS infrastructure, redundant content hosting, audience segmentation, deliverability testing, and continuous monitoring.
Key findings
- DNS Blocks Disrupt Authentication: Blocking at the DNS level prevents mail servers from resolving DNS records needed for SPF, DKIM, and DMARC, causing authentication failures and delivery issues.
- Image Rendering Problems in Blocked Regions: If email images are hosted on a subdomain of the blocked domain or served through a blocked CDN, those images may not display properly for recipients in those locations.
- Sender Reputation Impact: While localized, domain blocking can indirectly harm sender reputation due to reduced engagement, increased complaints, and potential spam classifications.
- Tracking and Engagement: DNS Block can prevent authentication and also impact click tracking, where if tracking links rely on the blocked domain, clicks from that region will not be recorded, skewing engagement metrics.
- Global deliverability is often unaffected: Assuming there are no major commercial services with systems inside the affected country and also bound to obey the country restrictions.
Key considerations
- Robust DNS Infrastructure: Ensure a robust and globally distributed DNS infrastructure to mitigate the impact of regional DNS blocks.
- Redundant Content Hosting: Use a CDN with a broad global presence and ensure redundancy in content hosting to minimize image rendering issues.
- Proper Authentication: Ensure SPF, DKIM, and DMARC are correctly configured to minimize deliverability issues in unaffected regions.
- Audience Segmentation: Consider segmenting your audience and using separate sending domains for regions with known domain blocks, if legally permissible, and compliant.
- Monitoring and Testing: Implement deliverability testing tools and closely monitor open rates and inbox placement in different regions to identify and address issues.
- Respect Local Laws: Ensure that your email marketing practices comply with the local laws and regulations of each country you are targeting.
What email marketers say
10 marketer opinions
Domain blocking in specific countries presents nuanced challenges for email deliverability and image rendering. While a domain block doesn't automatically jeopardize deliverability in unaffected regions (assuming proper email authentication is in place), it can indirectly impact overall sender reputation and engagement metrics. The inability to resolve DNS records in blocked regions can hinder authentication processes, while hosting images on subdomains of blocked domains leads to broken images for recipients in those countries. Legal and policy reasons behind the blocks necessitate respecting regional restrictions and segmenting audiences accordingly. Utilizing separate sending domains, robust CDNs, deliverability testing tools, and consistent monitoring are recommended mitigation strategies.
Key opinions
- Localized Impact: Domain blocks primarily affect deliverability and rendering within the specific countries where the block is enforced.
- Authentication Issues: DNS-level blocks can prevent mail servers from resolving DNS records needed for email authentication (SPF, DKIM), leading to delivery failures.
- Image Rendering Problems: If email images are hosted on a subdomain of the blocked domain, recipients in those countries may not be able to view them.
- Reputation at Risk: A domain block can indirectly hurt sender reputation due to reduced engagement metrics in the blocked region, as ESPs monitor these metrics.
- Legal/Policy Compliance: Domain blocking often stems from legal or policy restrictions that must be respected; audience segmentation becomes crucial.
- Engagement skewing: If the deliverability drops in a specific region there may be an impact on sender reputation.
Key considerations
- Proper Authentication: Ensure SPF, DKIM, and DMARC are correctly configured to minimize deliverability issues in unaffected regions.
- Segmented Sending: Consider segmenting your audience and using separate sending domains for regions with known domain blocks, if legally permissible.
- CDN Strategy: Use a CDN with a broad global presence and redundancy to ensure images are accessible even if some domains are blocked.
- Monitoring and Testing: Implement deliverability testing tools and closely monitor open rates and inbox placement in different regions to identify and address issues.
- Tracking Domain: If click tracking is essential, use a dedicated tracking domain, separate from the primary email sending domain, to avoid click-tracking issues due to domain blocks.
- Respect Local Laws: Ensure that your email marketing practices comply with the local laws and regulations of each country you are targeting.
Marketer view
Email marketer from StackExchange shares that domain blocking can sometimes be due to legal or policy reasons in certain countries. While it might not directly affect deliverability elsewhere, it's crucial to respect these regional restrictions and potentially segment your audience to avoid sending emails where they're not allowed, which can help maintain a positive sender reputation.
20 Feb 2023 - StackExchange
Marketer view
Marketer from Email Geeks explains that website blocking at a country level is country-specific and should not impact deliverability elsewhere if the sending reputation is good.
10 Jan 2024 - Email Geeks
What the experts say
6 expert opinions
Domain blocking in certain countries creates deliverability issues, primarily when the block occurs at the DNS level, preventing authentication protocols like SPF and DKIM from working. While deliverability outside of the blocked countries is generally unaffected, image rendering issues may arise if images are hosted on subdomains of the blocked domain or delivered through a blocked CDN. Redundancy in content hosting and robust global DNS infrastructure are crucial to mitigate these problems.
Key opinions
- DNS Blocking Impacts Authentication: If a domain is blocked at the DNS level, authentication protocols (SPF, DKIM) fail, leading to deliverability problems.
- Localized Image Rendering Issues: Images hosted on subdomains of blocked domains or served through blocked CDNs won't render for recipients in those countries.
- Limited Impact Outside Blocked Regions: Deliverability outside the blocked regions is typically unaffected, assuming no major commercial services are impacted.
Key considerations
- Robust DNS Infrastructure: Maintain a robust and globally distributed DNS infrastructure to minimize the impact of regional DNS blocks.
- Redundant Content Hosting: Use a CDN with a broad global presence and ensure redundancy in content hosting to avoid image rendering issues.
- Assess Blocking Methods: Understand how the blocking is handled to determine the specific impact on deliverability and rendering.
- Monitor Deliverability: Continuously monitor deliverability rates to identify any drops, especially in regions where domain blocking is known to occur.
Expert view
Expert from Word to the Wise shares that if you use a content delivery network (CDN) to host images or other content in your email and the CDN's domain is blocked in certain countries, those images may not display properly for recipients in those locations. They advise using a CDN with a broad global presence and ensuring redundancy in your content hosting strategy.
16 Aug 2021 - Word to the Wise
Expert view
Expert from Email Geeks confirms it depends on how the blocking is handled, but it’s a distinct possibility that the images won't render.
12 Mar 2025 - Email Geeks
What the documentation says
5 technical articles
Domain blocking in certain countries, particularly when implemented at the DNS level, significantly impairs email deliverability. This is due to the disruption of DNS lookups required for verifying email authentication protocols like SPF, DKIM, and DMARC, leading to delivery failures, emails being marked as spam, or outright rejection. Even if the direct impact on global deliverability is limited, a drop in engagement and an increase in complaints from blocked regions can negatively influence overall sender reputation and potentially trigger spam filters.
Key findings
- DNS Blocking Cripples Authentication: Domain blocking at the DNS level prevents mail servers from resolving DNS records needed for SPF, DKIM, and DMARC, causing authentication to fail.
- DMARC Failure: If blocking impacts DNS, then DMARC fails as it relies on DNS to validate both SPF and DKIM, which leads to email being rejected or quarantined.
- Reputation Impact: Although a localized block might not globally affect deliverability directly, decreased engagement and increased complaints from blocked regions can negatively influence sender reputation.
- Reduced Engagement: Domain reputation is influenced by engagement rates. Blocking a domain can lower engagement and result in potential spam classification.
Key considerations
- Monitor Sender Reputation: Closely monitor sender reputation metrics, especially after a domain block, to identify and address any negative impacts.
- Implement Robust Authentication: Ensure SPF, DKIM, and DMARC are properly configured to mitigate the effects of DNS blocking and maintain deliverability where possible.
- Analyze Regional Engagement: Analyze engagement metrics (open rates, click-through rates) by region to identify potential issues related to domain blocking.
- Audience Segmentation: Consider segmenting your audience and tailoring sending practices based on regional policies and restrictions to minimize the impact of domain blocking.
Technical article
Documentation from DKIM.org clarifies that if a domain is DNS blocked, the receiving server will not be able to retrieve the DKIM record to authenticate the email. This will probably cause issues with deliverability.
21 Oct 2024 - DKIM.org
Technical article
Documentation from DMARC.org shares that DMARC relies on DNS to validate both SPF and DKIM. If a blocking is impacting DNS in any way, DMARC fails, which leads to email being rejected or quarantined.
4 Oct 2022 - DMARC.org
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