How to prevent Gmail phishing warnings for internal emails with shortened links or shared sender names?
Michael Ko
Co-founder & CEO, Suped
Published 23 Jul 2025
Updated 19 Aug 2025
7 min read
Receiving a phishing warning for an internal email can be alarming, especially when the message is legitimate and crucial for daily operations. Many organizations face this challenge, often stemming from practices like using shortened links or having multiple individuals send from a shared departmental email address. It's a frustrating scenario that can disrupt communication and erode trust in internal systems. Understanding why Gmail flags these emails is the first step toward effective resolution.
This issue highlights a common misconception that internal emails are inherently safe from such scrutiny. However, modern email security systems, including Gmail's robust defenses, analyze all incoming mail rigorously, regardless of origin, to protect users from potential threats. This means even seemingly innocuous internal messages can trigger warnings if they exhibit characteristics commonly associated with phishing attempts.
Understanding Gmail's phishing detection
Gmail's sophisticated algorithms are constantly scanning for suspicious patterns and characteristics in emails that could indicate a phishing attempt. This includes examining sender identity, message content, and critically, the nature of any links embedded within the email. When a warning appears, it suggests that something in your email triggered one of these protective mechanisms. For more on general Gmail phishing warnings, you can read our guide on how to prevent them.
One of the primary culprits for internal email warnings is the use of shortened URLs. While convenient, these links obscure the final destination, a tactic frequently exploited by malicious actors to hide dangerous websites. Gmail, therefore, views them with suspicion, even when they point to legitimate services like Google Forms. This is a key reason why legitimate emails might trigger inconsistent suspicious link warnings.
Another significant factor involves shared sender names, where multiple users send from a single email address, but their individual display names vary. Gmail's advanced phishing and malware protection mechanisms are designed to detect impersonation. If a display name doesn't align with what Google expects for a given sender identity, it can raise a red flag, indicating a potential spoofing attempt.
The problem with shortened links
The convenience of shortened links often belies their security implications. Services like goo.gl, bit.ly, or custom shorteners, when used in emails, prevent recipients and email filters from immediately seeing the underlying domain. This lack of transparency is a major red flag for Gmail, as phishers commonly leverage these short URLs to disguise malicious destinations. It's a simple, yet effective, tactic for attackers.
Even if the shortened link points to a perfectly safe and legitimate resource, Gmail's security protocols prioritize user safety. They err on the side of caution to protect against potential threats. This is why you might see warnings even for links to trusted platforms, if those links have been shortened. The warning isn't necessarily about the destination itself, but the opaque nature of the link. Zoho Mail also advises against shortened URLs to avoid emails being marked as spam.
To mitigate this, always use the full, unshortened URL for links within your internal emails. This provides complete transparency to both recipients and email security filters, allowing them to verify the legitimacy of the destination before clicking. If branding is a concern, consider using a custom branded shortener that uses your own domain, but be aware that even these can sometimes be viewed with mild suspicion if not configured correctly. This will help you avoid looking like a phisher.
Example of using a full URL instead of a shortened onePlain text
Addressing shared sender names and display inconsistencies
When a single email address, such as a departmental alias, is used by multiple team members, each with their distinct display name, it can inadvertently trigger Gmail's phishing detection. The system may perceive this as an attempt to spoof an internal sender. For example, if "people@yourdomain.com" is used, but sometimes "Jane Doe" appears as the sender and other times "John Smith," Gmail's advanced phishing protection might flag it.
This behavior is rooted in Gmail's efforts to prevent impersonation attacks, where malicious actors mimic internal email addresses to trick employees. If Gmail cannot consistently verify the legitimate sender behind a shared address based on the display name, it raises a warning to protect users. While the intent is to safeguard, it can lead to frustrating false positives for legitimate internal communications.
To prevent these warnings, ensure consistency in how shared email addresses are presented. This might involve using a standardized display name for the shared mailbox, such as "People Team via Your Company Name," or by appending the individual sender's name to the shared alias, for example, "Jane Doe (People Team)." Clarity in the sender's identity is crucial for building trust with email clients.
Problematic sender name practices
Inconsistent display names: Using a shared mailbox but varying individual sender names, like "Jane Doe" or "John Smith" from the same people@yourdomain.com address. This creates ambiguity for Gmail's anti-phishing algorithms.
Generic aliases without context: Sending from a generic alias such as info@yourdomain.com without clear indication of the actual sender, making it harder for recipients and filters to verify legitimacy.
Recommended sender name practices
Standardized display names: Always use a consistent, clear display name for shared mailboxes, such as "People Team". This helps build a recognizable and trusted sender identity.
Individual sender identity: When appropriate, include the individual's name along with the shared alias. For example, "Jane Doe via People Team".
Brand consistency: Ensure your sender names align with your organizational branding and domain to reinforce legitimacy and prevent emails from being flagged.
Implementing email authentication for internal emails
Beyond content and sender names, robust email authentication is foundational to preventing phishing warnings. Even for internal emails, having correctly configured SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) records is vital. These protocols verify that your emails are legitimately sent from your domain and haven't been tampered with.
SPF specifies which mail servers are authorized to send email on behalf of your domain. DKIM adds a digital signature to your emails, allowing recipients to verify that the email was not altered in transit. DMARC ties these two together, providing instructions to receiving mail servers on how to handle emails that fail SPF or DKIM checks, and offering reporting capabilities. A misconfigured DMARC policy can lead to valid emails being flagged.
For organizations using Google Workspace, ensuring these authentication mechanisms are in place and properly aligned with your sending practices is paramount. Gmail heavily relies on these signals to determine trustworthiness. Regularly monitoring your DMARC reports can provide insights into potential authentication failures, helping you proactively address issues that could lead to phishing warnings or being put on a blacklist (or blocklist).
Protocol
Purpose
Impact on Phishing Warnings
SPF
Authorizes sending domains/IPs
Helps prevent sender spoofing by verifying the sending server, reducing chances of being blocklisted.
DKIM
Ensures message integrity
Verifies that the email content hasn't been altered, building trust and avoiding suspicious content flags.
DMARC
Policy for failed authentication
Instructs recipients how to treat unauthenticated mail and provides visibility into potential spoofing attempts. Check your DMARC record for proper configuration.
Monitor your reputation
Regularly monitor your domain's sending reputation through tools like Google Postmaster Tools. This provides valuable insights into how Gmail perceives your emails and can help you identify any issues before they escalate into persistent phishing warnings. If you notice issues, investigate further.
Views from the trenches
Best practices
Always use full, unshortened URLs in internal emails to ensure transparency and avoid suspicion from email filters.
Standardize display names for shared mailboxes to avoid confusing Gmail's anti-phishing mechanisms and maintain consistent sender identity.
Implement robust email authentication (SPF, DKIM, DMARC) for all your domains, even those primarily used for internal communication.
Common pitfalls
Using generic URL shorteners for links in internal emails, which can trigger automatic phishing warnings due to their opaque nature.
Allowing multiple individuals to send from a single email alias with inconsistent display names, leading to perceived impersonation.
Neglecting to implement or correctly configure DMARC, SPF, and DKIM for internal domains, leaving them vulnerable to spoofing and warnings.
Expert tips
Consider a custom branded URL shortener if unshortened links are not feasible, but ensure it aligns with your domain and is used judiciously.
Review your Google Workspace advanced phishing protection settings to understand how internal emails are being evaluated.
Leverage DMARC reporting to gain visibility into email authentication failures and potential internal spoofing attempts.
Marketer view
Marketer from Email Geeks says they always check for tracking links on URLs in the body, especially if the domains are different, as this can often be the source of phishing warnings.
2019-10-07 - Email Geeks
Marketer view
Marketer from Email Geeks says they've encountered issues with third-party URLs that might have been compromised, leading to emails being flagged.
2019-10-07 - Email Geeks
Strengthening your internal email security posture
Preventing Gmail phishing warnings for internal emails with shortened links or shared sender names requires a multi-faceted approach. It involves a clear understanding of how email security mechanisms interpret sender identity and link transparency. By moving away from generic URL shorteners and adopting consistent, transparent sender naming conventions, you can significantly reduce the likelihood of these disruptive warnings.
Beyond these immediate adjustments, investing in proper email authentication protocols (SPF, DKIM, DMARC) for all your domains will provide a strong foundation for trust and deliverability. This comprehensive strategy not only mitigates current issues but also builds a more resilient and secure internal email environment, ensuring your important communications reach their intended recipients without unnecessary warnings or disruptions.
