Can a competitor damage my domain reputation by sending spam with links to my site?
Matthew Whittaker
Co-founder & CTO, Suped
Published 16 Jul 2025
Updated 17 Aug 2025
7 min read
The question of whether a competitor can intentionally damage your domain's email reputation by sending spam that links back to your site is a serious concern for many businesses. It raises fears about unfair practices and the potential for unwarranted harm to your online presence and email deliverability.
While it might seem like a far-fetched scenario, the short answer is yes, it is possible for such a negative practice to affect your domain reputation. However, the good news is that email service providers (ESPs) and internet service providers (ISPs) have sophisticated systems in place to prevent easy manipulation and mitigate the impact of such attacks. The challenge often lies in distinguishing a malicious attack from other factors affecting your sender reputation.
Protecting your domain's reputation
Email domain reputation acts like a credit score for your email sending activities, indicating how trustworthy your domain is to mailbox providers. Every domain and hostname present in an email, including those within links in the message body, is assessed for its reputation. This comprehensive approach is essential to prevent spammers from simply using clean sending domains while linking to untrustworthy or malicious sites.
If a domain appears frequently in spam, regardless of the sender's actual email address, it starts to accumulate a negative reputation. Mailbox providers like Google and Microsoft will flag these domains, potentially leading to deliverability issues for legitimate senders who also use those domains. This mechanism makes it harder for spammers to operate and protects the integrity of the email ecosystem. A domain's reputation is influenced by various factors, including bounce rates, spam complaints, and user engagement.
Understanding domain reputation
Comprehensive assessment: ISPs and ESPs evaluate the reputation of every domain and IP address associated with an email, including the sender's domain, IP addresses, and any domains found in the links within the email body. This is why domain reputation is a critical factor for your email deliverability.
Spam linkage: If your domain is repeatedly seen in emails that generate a high volume of spam complaints or land in spam folders, your domain's reputation will suffer, even if the emails weren't sent directly from your servers or under your explicit authorization. This can also lead to your domain being placed on a blacklist (or blocklist).
While uncommon, a malicious competitor could try to damage your domain reputation by crafting and sending large volumes of spam emails that contain links to your website. Their goal would be to trigger spam filters and generate high complaint rates associated with your domain, thereby eroding its trustworthiness. This is often referred to as a form of negative SEO or a negative email attack.
Such an attack would typically involve using separate, often disposable, sending domains and IPs to distribute the spam, making it harder to trace back directly to the competitor. However, because the content includes links to your domain, mailbox providers would still associate that negative activity with your site. The severity of the damage depends on the scale of the attack and the efficacy of spam filtering systems in isolating the malicious intent.
It is important to remember that such deliberate sabotage is rare compared to issues arising from legitimate (but poorly managed) email sending practices, such as problematic affiliate marketing or outdated list management. Google, for instance, has stated it has systems in place to largely ignore spammy backlinks in the context of SEO, but email deliverability can be more sensitive. The most common cause of a damaged domain reputation is usually internal, or from third-party partners you authorize.
Competitor attack
Motivation: Intentional sabotage to lower your email deliverability or SEO rankings by associating your domain with spam.
Execution: Spam campaigns are sent from unrelated domains, but contain links pointing to your site.
Detection challenges: Hard to prove malicious intent directly, as the emails aren't sent from your infrastructure.
Affiliate misconduct
Motivation: Affiliates using aggressive or non-compliant sending tactics to promote your products or services, potentially damaging your brand.
Execution: They send emails with links to your site, but from their own sending domains, often to cold or unengaged lists.
Your liability: You can be held accountable for their actions under regulations like CAN-SPAM, especially if you were aware of their practices.
If you suspect your domain reputation is suffering due to external spam linking, the first step is to gather evidence. Ask users who report suspicious emails to provide the full email headers, not just screenshots or forwards. Full headers contain crucial information about the email's origin, routing, and authentication status, which can help in your investigation.
Monitor your domain's reputation using tools like Google Postmaster Tools. This will show you your domain's sending reputation with Gmail users, including spam rates and delivery errors. Look for sudden spikes in spam complaints or drops in deliverability that coincide with unusual activity. Remember, even if the main domain's reputation is stable, a subdomain, like one used for a specific regional audience, can experience issues independently. For more on this, check out how subdomain spam complaints affect reputation.
If you identify specific spam campaigns linking to your site, analyze the content and the sender's details. This can help determine if it's a competitor, an unruly affiliate, or a completely unrelated malicious actor. Understanding the source is key to taking appropriate action, which could range from contacting the sender (if identifiable) to disavowing links for SEO purposes (though this is less effective for email deliverability issues).
Retrieve email headers
To investigate suspicious emails, always request the full email headers from the recipient. This data is critical for understanding the email's journey and identifying potential red flags like SPF or DKIM failures, or the actual sending IP and domain. A screenshot or simple forward often doesn't provide enough detail.
Example of full email headersplain text
Received: from mail-tester.com (mail-tester.com [1.2.3.4]) by mx.google.com with ESMTPS id abcdef123456789; Fri, 1 Jan 2025 12:00:00 -0000 (UTC)
Authentication-Results: mx.google.com;
dkim=pass header.i=@yourdomain.com header.s=default header.b=abcdef;
spf=pass (google.com: domain of yourdomain.com designates 5.6.7.8 as permitted sender) smtp.mailfrom=yourdomain.com;
dmarc=pass (p=none sp=none dis=none) header.from=yourdomain.com
From: "Your Name" <info@yourdomain.com>
To: recipient@example.com
Subject: Important Update
Date: Fri, 1 Jan 2025 12:00:00 +0000
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Message-ID: <unique-message-id@yourdomain.com>
The most effective defense against any form of domain reputation damage, whether from competitors or otherwise, is robust email authentication. Implementing DMARC (Domain-based Message Authentication, Reporting, and Conformance), SPF (Sender Policy Framework), and DKIM (DomainKeys Identified Mail) is crucial. These protocols help mailbox providers verify that emails purportedly from your domain are indeed authorized to send on your behalf. This makes it much harder for malicious actors to spoof your domain or send emails that appear legitimate but are not.
Regularly monitor your domain's standing on various email blocklists and blacklists. While a direct competitor attack on your domain's reputation via spam links might be ignored by some systems, being listed on a blocklist will severely impact your deliverability. Timely detection and delisting are vital for recovery. You can also monitor blocklists to stay informed.
Maintain strong sender hygiene by sending only to engaged subscribers and regularly cleaning your email lists to remove inactive or invalid addresses. Avoiding spam traps is paramount, as hitting them can severely damage your reputation. By consistently demonstrating good sending practices, you build a strong, resilient domain reputation that is harder to negatively impact, regardless of external attempts. This is crucial for preventing spam backlinks from ruining your reputation.
Safeguarding your email presence
While it's unsettling to consider a competitor intentionally harming your domain's reputation, email infrastructure is designed with layers of defense. Mailbox providers are increasingly sophisticated at identifying and mitigating such attacks by penalizing the actual senders of spam, even if they link to legitimate sites. However, the linked domain will still face some scrutiny and potential temporary issues.
Your best strategy remains proactive. Maintain excellent email authentication, diligently monitor your domain and IP reputation, and ensure all your legitimate sending practices are impeccable. By doing so, you build a robust reputation that is resilient to external threats, allowing you to focus on your actual email marketing and deliverability goals without undue interference.
Views from the trenches
Best practices
Actively monitor your domain's reputation using tools like Google Postmaster Tools.
Implement and enforce strong email authentication protocols like DMARC, SPF, and DKIM.
Regularly clean your email lists to remove unengaged or invalid addresses.
Common pitfalls
Assuming malicious spam linking is always a competitor attack; consider affiliate misconduct first.
Relying solely on screenshots or forwarded emails for investigation instead of full headers.
Ignoring subtle dips in domain reputation or minor increases in spam complaints.
Expert tips
Prioritize investigating any affiliate programs for non-compliant sending behaviors.
Understand that mailbox providers assess the reputation of all domains in an email, including linked ones.
A strong, consistent sending history from your domain provides significant resilience against negative attacks.
Expert view
Expert from Email Geeks says that every domain and hostname within an email, including linked domains, possesses a reputation, meaning external spam linking can indeed damage your domain reputation.
2023-11-03 - Email Geeks
Expert view
Expert from Email Geeks explains that the alternative to assessing linked domain reputation would be allowing spammers to use clean sending domains while freely linking to anything, which is why reputation is applied comprehensively.
Google and 
Microsoft will flag these domains, potentially leading to deliverability issues for legitimate senders who also use those domains. This mechanism makes it harder for spammers to operate and protects the integrity of the email ecosystem. A domain's reputation is influenced by various factors, including bounce rates, spam complaints, and user engagement.
Gmail users, including spam rates and delivery errors. Look for sudden spikes in spam complaints or drops in deliverability that coincide with unusual activity. Remember, even if the main domain's reputation is stable, a subdomain, like one used for a specific regional audience, can experience issues independently. For more on this, check out how subdomain spam complaints affect reputation.
