Check if an email address exists without sending any email. Use php stream_socket_client.
在不发送邮件的情况下检测邮件地址是否有效
php check.php [email protected]这是一个草稿，仅仅提供思路，也许它只会在某些情况下工作（比如 qq.com）
这个工具依赖于 25 端口，然而部分服务商（TX Cloud）默认屏蔽了 25 端口，连不上 SMTP 服务器
部分邮件服务商会屏蔽家宽的 IP，导致 RCPT TO 不可用，因此本地测试可能会失败，比如微软和 Zoho
# Microsoft
550 5.7.1 Client host [49.*.*.*] blocked using Spamhaus. To request removal f
rom this list see http://www.spamhaus.org/lookup.lasso (S3130). [VE1EUR01FT012.e
op-EUR01.prod.protection.outlook.com]
# Zoho
550 Mail rejected by <Zoho Mail> for policy reasons. We generally do not accept
email from dynamic IP's as they are typically used to deliver unauthenticated SM
TP e-mail to an Internet mail server. http://www.spamhaus.org maintains lists of
dynamic and residential IP addresses. If you are not an email/network admin ple
ase contact your E-mail/Internet Service Provider for help. Email/network admins
, please contact <[email protected]> for email delivery information and suppo
rt
TL 里发现了 amaurymartiny/check-if-email-exists，一个同样功能的小脚本，然而实际上是跑不起来的，想提个 PR 改改，可惜不太会，就用 PHP 写了个同样功能的
- 默认域名就是邮件服务器，不会查询 MX 记录
OUPUT只会取到最后的221 Bye（就是这个改不来