February 2022 Summaries

Email validation in C# helps reduce bounced messages, protect sender reputation, and improve campaign effectiveness by filtering malformed or nonexistent addresses. Basic syntax checks can use the built-in System.Net.Mail.MailAddress class, although it may accept addresses without a conventional top-level domain, while regular expressions offer greater control over accepted formats but cannot confirm that an address exists and can become difficult to maintain. ASP.NET applications can use Data Annotations such as Required, EmailAddress, and RegularExpression to provide client-side form validation and customized error messages. For more extensive verification, external libraries including GemBox.Email and EASendMail can check syntax, domains, mail servers, and sometimes mailbox existence, though these network-based checks may be affected by DNS, firewall, ISP, or server-connection limitations. After validation, email delivery can be tested safely in a sandbox environment such as Mailtrap to inspect SMTP traffic without sending messages to real recipients.