Summary
The choice between using subdomains and cousin domains for email marketing often sparks debate between marketing and security teams. While marketing prioritizes deliverability and brand consistency, security teams aim to protect the core domain from potential reputation damage and phishing attacks. This tension frequently leads to security teams suggesting cousin domains (domains similar to, but distinct from, the primary brand domain) as a workaround. The rationale behind this often stems from a risk-averse approach where isolating marketing email activity to a separate, less critical domain is perceived as a safer bet. However, this strategy can introduce its own set of problems, including diluted brand identity, potential for increased spoofing, and challenges in maintaining a cohesive email deliverability strategy.
Key findings
- Risk isolation: Security teams often advocate for cousin domains to isolate the risk of email marketing activities impacting the main corporate domain's reputation. This is done to protect the primary domain from being blocklisted (or blacklisted) due to marketing email issues.
- Misunderstanding email: A common criticism is that security personnel may not fully grasp the intricacies of email deliverability and how modern authentication protocols like SPF, DKIM, and DMARC work across domains and subdomains.
- Brand protection versus deliverability: While brand protection is a goal for both teams, their methods conflict. Security focuses on preventing compromise of the primary domain, potentially at the cost of marketing's brand continuity and email deliverability rates.
- Cousin domain risks: Cousin domains can still be targeted by phishers (or spoofers) who register similar-looking domains, potentially confusing recipients and undermining brand trust. Protecting against these cousin domain attacks becomes another security concern.
Key considerations
- Unified goals: Both security and marketing aim for the company's success. Collaborative efforts and clear communication are essential to find solutions that satisfy both security requirements and marketing objectives.
- Subdomain control: IT can maintain control over subdomains, ensuring that security measures and authentication protocols are correctly implemented. This allows marketing to use brand-aligned domains while IT manages the technical security aspect. Consider best practices for email domain authentication across corporate and marketing mail.
- Reputation management: Subdomains can offer adequate separation for reputation management. If properly configured, negative engagement on a marketing subdomain might not severely impact the primary domain, although total isolation is not guaranteed. Understand how subdomain deliverability issues affect parent domains.
- Long-term brand impact: Using cousin domains may provide short-term security isolation but could dilute brand recognition and trust in the long run. A strong brand identity in email is crucial for recipient engagement and loyalty.
What email marketers say
Email marketers often express frustration when security teams prevent them from using corporate domains or subdomains for email campaigns, pushing instead for cousin domains. They highlight that this approach can hinder brand consistency and overall marketing effectiveness, arguing that with proper setup, subdomains offer sufficient isolation for deliverability while maintaining brand integrity. The core concern for marketers is achieving inbox placement and engagement without compromising the brand image.
Key opinions
- Frustration with security: Many marketers are frustrated by security teams dictating domain usage without fully understanding email marketing nuances, often feeling their deliverability concerns are secondary.
- Brand dilution: Using a cousin domain can dilute brand identity, making it harder for recipients to recognize and trust emails from the brand, especially if there are multiple domains involved.
- Lack of understanding: Marketers often perceive that security teams lack an in-depth understanding of email deliverability best practices, leading to overly conservative domain policies.
- Prioritizing deliverability: Marketers prioritize inbox placement and engagement, believing that a subdomain approach, when properly managed, offers the best balance of brand trust and deliverability without unnecessary risk to the root domain.
Key considerations
- Subdomain benefits: Using subdomains allows for clear segmentation of email traffic (e.g., transactional, marketing, sales) which helps in managing sender reputation more granularly and efficiently. Learn why to use email subdomains for deliverability.
- Reputation management: Marketers believe that isolating high-volume or potentially risky email streams to a specific subdomain minimizes the risk to the main domain. This allows for more aggressive marketing tactics without jeopardizing critical corporate communications.
- Collaboration is key: Effective communication and collaboration with IT and security teams are vital. Marketing needs to educate security on deliverability best practices, while security should explain their risk mitigation strategies.
- Long-term strategy: A long-term view suggests that maintaining a consistent brand identity across all email communications, including marketing, is beneficial. This is best achieved through subdomains rather than disjointed cousin domains. Consider moving promotional campaigns to a dedicated subdomain.
Marketer view
Marketer from Email Geeks laments that security personnel frequently advise against using corporate domains or subdomains for email marketing, instead suggesting cousin domains. They express frustration over this recurring issue, seeing it as an unnecessary hurdle.
Marketer view
Marketer from Email Geeks observes that security teams often assume marketers won't adhere to their guidelines, which leads them to implement policies that keep potential deliverability problems outside their direct area of responsibility. This approach, while protective for security, can create friction.
What the experts say
Experts in email deliverability and security often highlight a significant knowledge gap between traditional IT security mindsets and the realities of modern email ecosystems. They argue that a blanket ban on subdomains for marketing, in favor of cousin domains, frequently stems from a misunderstanding of how email authentication (like DMARC, SPF, and DKIM) functions and how sender reputation is managed. While security's intent is to protect the primary brand, their recommended solutions can inadvertently undermine deliverability and brand trust, rather than truly enhancing security.
Key opinions
- Email protocol knowledge gap: Experts believe that some security professionals lack a deep understanding of email architecture and authentication, leading to misinformed policies regarding domain usage.
- Cousin domain limitations: Attempts to establish industry-wide mechanisms to link or track cousin domains (like RDBD) have not gained significant traction, underscoring the ongoing challenge of managing these detached entities.
- Reputation inheritance: Subdomains inherit some reputation from the parent domain. While this can be a risk, it also means a well-managed subdomain can leverage the parent's positive standing. Conversely, a poor reputation on a subdomain can still negatively reflect on the main domain, albeit to a lesser extent, highlighting the complex nature of reputation inheritance.
- Subdomain as a better solution: Many experts argue that subdomains offer a more effective balance between brand alignment and reputation isolation, especially when coupled with robust DMARC policies.
Key considerations
- Comprehensive authentication: Implementing a strong DMARC policy on the primary domain and all subdomains is critical. This ensures that unauthorized use of any domain or subdomain is detected and acted upon, providing robust protection. A simple guide to DMARC, SPF, and DKIM can help.
- Internal education: Bridging the gap between security and marketing requires educating both teams on each other's priorities and the technical aspects of email deliverability and security.
- Shared responsibility: Deliverability and security should be a shared responsibility. Security teams can enable marketing to use subdomains while enforcing strict compliance and monitoring protocols. Organizations should focus on fixing email deliverability issues collaboratively.
- Holistic view: A comprehensive approach considers both the immediate security risks and the long-term impact on brand reputation, customer trust, and marketing effectiveness, rather than resorting to superficial workarounds like cousin domains.
Expert view
Expert from Email Geeks indicates that security personnel sometimes lack a comprehensive understanding of how email functions, which can lead to policies that are not optimally aligned with email deliverability best practices. This gap in knowledge can inadvertently create challenges for marketing efforts.
Expert view
Expert from Email Geeks mentions previous attempts to create systems like RDBD (Root Domain Blocklist Data) aimed at linking cousin domains, but notes that such endeavors have not always been deemed useful or widely adopted by internet engineering task forces. This suggests the complexity of addressing cousin domain issues at a foundational level.
What the documentation says
Official documentation and technical guides consistently advocate for the use of proper email authentication protocols (SPF, DKIM, DMARC) across all sending domains and subdomains. They highlight that subdomains are designed to segment traffic and manage reputation effectively while maintaining hierarchical control under the parent domain. Cousin domains, while offering a degree of isolation, introduce challenges in unified brand management and can still be exploited for spoofing if not carefully monitored and protected.
Key findings
- Subdomain purpose: Documentation confirms that subdomains serve to separate email communication from the root domain, allowing for improved reputation management and organized traffic flow.
- Authentication importance: All sending domains, including subdomains, require robust authentication records (SPF, DKIM, DMARC) to verify sender identity and prevent spoofing. SPF for subdomains is critical.
- Domain spoofing risks: Attackers frequently create domain names or subdomains that visually resemble legitimate ones to impersonate brands, emphasizing the need for active monitoring for domain spoofing across all domain types, including cousin domains.
- Security through policy: Security measures can be enhanced for email data defense by using unique domain names for emails, often achieved through subdomains, to apply specific security protocols.
Key considerations
- Centralized control: Subdomains allow a company's IT or security team to maintain centralized control over DNS records and email authentication, ensuring consistency and compliance with security policies. This simplifies management compared to disparate cousin domains.
- Brand integrity: Official guides often imply that using subdomains helps maintain a consistent brand identity across all email communications, which is important for recipient trust and engagement. Cousin domains can fragment this identity.
- Monitoring and reporting: Regardless of the domain type, comprehensive DMARC monitoring is recommended to gain visibility into email authentication results and identify potential spoofing attempts. This monitoring is more streamlined with a subdomain strategy.
- Defined purpose: Subdomains are defined as prefixes that direct traffic to different IP addresses while maintaining the same root domain. This technical definition supports their use for isolating different email streams for specific purposes without needing an entirely new, potentially unbranded, domain.
Technical article
Documentation from Mailgun explains that a subdomain is essentially a prefix that precedes the root domain, commonly utilized on websites to direct traffic to a distinct IP address while preserving the primary domain identity. This structural definition underscores its suitability for segmenting email traffic under a unified brand.
Technical article
Documentation from AutoSPF emphasizes that SPF acts as a critical gatekeeper, ensuring that only authorized servers can send emails on behalf of a specific domain. This mechanism is vital for significantly enhancing email security and is fully applicable to subdomains, allowing for granular control over sending permissions.
Related resources
15 resources
Related pages
Why do companies use cousin domains for email campaigns?
Why use email subdomains and when to implement them for deliverability?
Can negative email engagement on a subdomain affect the primary domain's reputation?
What are the best practices for email domain authentication across corporate and marketing mail?
A simple guide to DMARC, SPF, and DKIM
How email blacklists actually work: a simple guide
Why your emails are going to spam in 2024 and how to fix it
Should I use a subdomain or my main domain for marketing emails?
What is the best practice for selecting a subdomain for marketing emails and how does it impact deliverability?
How do subdomain deliverability issues affect parent domains, and what are the primary causes of email deliverability problems?
