To verify your custom domain for Gmail (Google Workspace) Hotmail/Outlook (Microsoft 365) Yahoo Mail , you must add specific TXT records to your domain's DNS settings

Modern ESP requirements have made "verified" lists a necessity rather than a luxury for businesses.

: Uses SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) records—both of which are TXT records added to a domain's DNS. : Requires text (SMS) verification for 2-Step Verification , though users should be cautious of unsolicited codes.

: A TXT record that lists which IP addresses are allowed to send mail on behalf of your domain. DKIM (DomainKeys Identified Mail)

Verify: Enter the 6-digit code sent to your phone to finish the setup. Hotmail / Outlook (Microsoft) Text Verification

• Privacy: Google, Microsoft, and Yahoo block "MX lookup" verification bots.
• Rate Limiting: Attempting to guess or verify addresses is illegal under the Computer Fraud and Abuse Act (CFAA) in the US and similar laws globally.
• The Only Safe Method: Send an email with a TXT verification code. If the user responds, it is verified.

1. Indicator Analysis

• The String Structure: The term gmailcom hotmailcom yahoocom represents a filtering method used by cybercriminals to organize leaked data. Attackers often sort massive databases of millions of emails by domain provider to target specific authentication systems or to sell "cleaner" lists to other criminals.
• The "txt" Extension: This explicitly refers to text files (.txt). In the context of data breaches, credentials are almost always distributed in plain text files formatted as email:password.
• The Term "Verified": This is a critical operational keyword in the "Account Takeover" (ATO) ecosystem.

  Third-Party Login (OAuth with TXT): Some platforms verify a user’s actual Gmail/Hotmail/Yahoo account by sending a TXT-coded verification email. You copy the code from the email and paste it back into the app.