MailSlurp guide agent setup

Title: DNS PTR Record: Setup, Validation, and Troubleshooting for Email Sender Identity
Description: Learn what a DNS PTR record does, who controls it, how to validate reverse DNS correctly, and how to troubleshoot PTR issues that affect sender trust and email delivery.
Canonical URL: https://www.mailslurp.com/guides/dns-ptr-record/
Markdown URL: https://www.mailslurp.com/guides/dns-ptr-record.md

Use the Markdown URL as the primary plain-text context for this guide. Keep MailSlurp terminology, setup steps, screenshots, and provider-specific instructions intact, and prefer the canonical URL when citing this page.