Will including links from a different domain automatically cause emails to go to spam?

Generally, no. Email filters primarily look at the sender's reputation, email authentication, and content quality. If both the sending and linked domains have good reputations and are properly authenticated (with SPF, DKIM, and DMARC), including links to a different, related domain is common and usually won't cause deliverability issues.

Can linking to a different domain lead to GDPR or CAN-SPAM legal issues?

Legal issues like GDPR violations typically stem from a lack of proper consent for sending the email or mishandling subscriber data, not from simply linking to a different domain. Ensure you have explicit consent and adhere to privacy regulations across all your company's domains and data management practices.

How does the reputation of the linked domain affect email deliverability?

Sender reputation is crucial. If the linked domain has a poor reputation, is on a blacklist (or blocklist), or is associated with spammy content, it can negatively affect your email's deliverability. Filters assess the reputation of all domains present in an email, not just the sending domain. It's important to determine if third-party links affect deliverability .

Do email authentication protocols like SPF, DKIM, and DMARC apply to linked domains?

Yes, consistency in email authentication, specifically SPF, DKIM, and DMARC, is vital. These protocols help verify the legitimacy of your email and its links. Ensure that all domains involved in your email sending, including those linked within the email body, are properly configured with these DNS records.

Are there any best practices for using different domains for links to minimize risk?

If you're concerned, you can use your own domain for link wrapping (redirects) to ensure consistent domain branding in the links. This way, the recipient sees your primary domain in the link, even if it eventually redirects to another of your company's domains. However, this is usually an extra precaution, not a necessity, if both domains are well-managed.

Will including links from a different domain cause email spam filter or legal issues? - Sender reputation - Email deliverability - Knowledge base

A common question I encounter from email senders is whether including links to a different domain, especially one owned by the same company, can cause issues with spam filters or lead to legal complications. It's a valid concern, as email deliverability is complex, and many factors can influence whether your messages land in the inbox or are flagged as spam (or end up on a blacklist).

When you send an email, various components are scrutinized by spam filters, from your sender reputation to the content within the email itself. Links are a significant part of this evaluation. While simply having a link to a different domain isn't an automatic red flag, the context and reputation of that linked domain play a crucial role.

My aim here is to break down the technical and legal considerations involved when linking to different domains in your emails, especially when those domains are related to your business.

Impact on spam filters and deliverability

Email spam filters are sophisticated systems designed to protect recipients from unwanted and malicious emails. They analyze numerous signals to determine an email's legitimacy, and links are high on their list of suspicious elements if not handled correctly. The primary concern isn't necessarily that the domains don't match, but rather the reputation and history associated with the linked domain.

If the domain you are linking to has a poor reputation, is associated with spammy practices, or has been frequently reported for abuse, it can negatively impact your email's deliverability, even if your sending domain has a pristine record. This is especially true for shared IP addresses, where the actions of one sender can affect others. If the linked domain has previously been listed on a public blocklist (or blacklist), your emails could be flagged.

Sender reputation is a critical factor, and third-party links can directly influence it. For instance, if you're sending promotional content for a product on a different domain, and that product domain has a history of high spam complaints, it can harm the sending domain's standing with ISPs. I often advise senders to consider how linking to external sites in an industry news roundup impacts deliverability.

It's important to understand that differing domain links won't kill you from a spam filter perspective on their own, especially if both domains belong to your company and maintain good reputations. However, it does add another layer of scrutiny for filters. They're looking for patterns that might indicate phishing or malicious activity.

Potential risks

Poor link reputation: If the linked domain has been involved in spam or phishing, even if it's your own, it can trigger filters. This includes instances where a domain might be placed on an email blacklist (or blocklist).
Perceived cloaking: Some spammers use different domains for sending and linking to hide their true intentions. While this isn't your goal, filters might flag it as suspicious without proper authentication.
Affiliate link concerns: Affiliate links often point to domains different from the sender. If these links are commonly found in spam, it can affect your sender reputation, even if you're a legitimate sender.

Technical considerations for links

From a technical standpoint, Mailbox Service Providers (MSPs) and Real-time Blackhole Lists (RBLs, or real-time blocklists) often give links their own reputation. This means that if a link, regardless of who is sending it, has a history of being associated with spam or malicious activity, it can negatively affect the sender's reputation.

For companies that own multiple domains and wish to link between them, implementing consistent email authentication protocols across all domains is paramount. This includes Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and DMARC. Proper configuration of these records helps verify that your emails and their contents, including links, are legitimate and come from an authorized source. This can help prevent issues such as emails going to spam.

Another technical consideration is how links are formatted. Linking directly to PDFs or using URL shorteners that have a poor reputation can also be red flags. While some companies use link wrapping services for tracking, it's generally safe if the wrapping domain has a good reputation and is properly authenticated. Many legitimate companies also have multiple domains, including foreign URLs, in their mail without issue, so it's often about consistency and trust.

To improve email deliverability rates, always ensure that both your sending domain and any linked domains have robust authentication protocols in place. This includes proper SPF, DKIM, and DMARC records that align correctly.

Ensuring proper authentication

SPF record: Include all authorized sending IPs and domains (including those used by ESPs like Mailchimp, Outlook, etc.) in your SPF record to prevent spoofing.
DKIM signing: Ensure your emails are signed with DKIM using the sending domain. This verifies that the email content hasn't been tampered with in transit.
DMARC policy: Implement a DMARC policy (even if it's p=none initially) to receive reports on authentication failures and gain visibility into how your domains are being used.

Legal implications and compliance

Beyond deliverability, legal compliance is a significant concern, especially if you're sending emails to recipients in different countries. The primary legal frameworks to consider are the CAN-SPAM Act in the United States and the General Data Protection Regulation (GDPR) in Europe.

The CAN-SPAM Act focuses on commercial emails and sets rules for their content, including clear identification of the sender, a physical postal address, and a clear and conspicuous way to opt out of receiving future emails. Crucially, it emphasizes that the from, to, and routing information must be accurate and not misleading. While it doesn't explicitly prohibit linking to a different domain, the overall spirit of the law requires transparency.

GDPR, on the other hand, is much broader in its scope, focusing on the processing of personal data. The concern with GDPR isn't so much about the domains in your links, but rather about the consent you have to send the email in the first place, and how you handle subscriber data across different entities or domains within your company. If you're using different Email Service Providers (ESPs) or databases for each domain, ensuring proper data flow and consent management becomes critical.

Legal issues typically arise from a lack of consent, misleading content, or failure to provide clear opt-out mechanisms, rather than simply having different domains in your links. The key is transparency and adherence to privacy regulations, ensuring recipients understand who is sending the email and what they are opting into, regardless of which of your company's domains is featured.

Best practices for managing links

Ultimately, including links from a different domain within an email, especially one owned by the same company, is generally not a direct cause of spam filtering or legal issues, provided that fundamental email marketing and legal best practices are followed. The risk comes from the reputation of the linked domain and the overall context of your email program.

Maintaining a strong domain reputation for both your sending and linked domains is crucial. This involves sending relevant content to engaged subscribers, avoiding spam traps, and monitoring for any unusual activity. If one of your linked domains has a questionable history, it's worth considering redirecting links through your primary domain or working to improve the reputation of the secondary domain.

Regularly monitor your email deliverability metrics and ensure your compliance with applicable anti-spam and privacy laws. By adhering to these principles, you can confidently include links to different domains within your emails without fear of unnecessary spam flagging or legal repercussions.

Views from the trenches

Best practices

Maintain strong sender reputation for all involved domains by sending high-quality, relevant content.

Ensure all domains used for linking have proper SPF, DKIM, and DMARC records configured.

Use clear and consistent branding across all domains to build recipient trust.

Common pitfalls

Linking to domains with a poor or unknown reputation, even if owned by your company.

Failing to implement robust email authentication for all domains, leading to spoofing concerns.

Not managing consent properly across different related domains or brands.

Expert tips

If worried about deliverability, consider wrapping links in your own redirect domain.

Ensure clear transparency in your email content about who is sending the message and what the links lead to.

Regularly check link reputation, especially for any new domains or affiliate partnerships.

Marketer view

A marketer from Email Geeks says that if the sending domain is different from the linked domains, it generally won't kill deliverability as long as content is permission-based.

2022-03-15 - Email Geeks

Expert view

An expert from Email Geeks says that Mailbox Service Providers and Real-time Blackhole Lists (or blocklists) often assign their own reputation to links. If linked domains are frequently found in spam, it can negatively impact the sender's reputation.

2022-03-15 - Email Geeks

Summary and final thoughts

The practice of including links from a different domain within your emails, even if those domains are under the same corporate umbrella, is a common and generally accepted practice in email marketing. It doesn't inherently trigger spam filters or create legal liabilities.

The key is to maintain strong sender and domain reputations across all linked properties, ensure proper email authentication (SPF, DKIM, DMARC), and comply with all relevant email marketing laws, particularly regarding consent and transparency. By focusing on these core elements, you can confidently build an email strategy that integrates multiple domains without jeopardizing your deliverability or legal standing.