|RegexCheck||0||Check e-mail address syntax only, via regular experssion (can be customized with RegexPattern property). Very fast and does not make any network queries.|
|DnsQuery||1||In addition to syntax check, do DNS MX query against the domain name part of the e-mail address to determine which SMTP MX server is responsible for delivering e-mail to the given domain. Slower than just syntax check but more accurate as invalid domains are filtered out.|
|SmtpConnection||2||In addition to the previous option, make an attempt to connect to the SMTP MX server determined at the previous stage. If multiple MX servers have been detected and the server having the highest priority is not responding, will also try other MXes of this domain, in accordance with their priorities. Slower than just a DNS MX check but more accurate as it filters out the domains with dead SMTP MX servers.|
|SendAttempt||3||This method not just connects to SMTP MX server but also submits the sender and recipient (where the recipients is the e-mail address being examined) to that MX server. The slowest and the most accurate method.|
|OK||4||Verify(String) method returns this value when the e-mail address check passed successfully. Has the same meaning for Result property of Verified event.|
The values of this type can be used as both input parameters (when they define how deeply the e-mail address check should go) and return values (when they show at which stage the verification procedure failed).
For instance, if you set the desired level of verification to, let's say, DnsQuery, it means MailBee will do syntax check and DNS MX query check. If both checks are OK, the return value will be OK. Otherwise, the return value will be the level at which the verification failed. For instance, if it failed at syntax check against a regular expression pattern, the return value will be RegexCheck.
|Use advanced methods of verification (SmtpConnection and SendAttempt) with care.
See below the common pitfalls of e-mail address verification which involves making test SMTP connections.