Validating an email address in php Sex chat without paying to message them
This will mess up attempts to validate the address. Please try 550-5.1.1 double-checking the recipient's email address for typos or 550-5.1.1 unnecessary spaces. answer=6596 w41si3198459wfd.71 Lines prefixed with numeric codes are responses from the SMTP server. Many mail servers will not return this information as a means to prevent against email address harvesting by spammers, so you cannot rely on this technique.Honestly, if you're attempting to validate an address the best approach is to use a simple regex to block obviously invalid addresses, and then send an actual email with a link back to your system that will validate the email was received. However you may have some success at cleaning out some obviously bad email addresses by detecting invalid mail servers, or having recipient addresses rejected as above.I have come across this PHP code to check email address using SMTP without sending an email.Has anyone tried anything similar or does it work for you?This article uses the term email address to refer to the addr-spec defined in RFC 5322, not to the address that is commonly used; the difference is that an address may contain a display name, a comment, or both. [email protected] made up of a local-part, an @ symbol, then a case-insensitive domain.Although the standard specifies the local part to be case-sensitive, in practice the mail system at may treat John.It also checks for common typos witch is quite useful. Assuming it's the user's address, some mail servers do allow the SMTP VRFY command to actually verify the email address against its mailboxes.Most of the major site won't give you much information; the gmail response is "if you try to mail it, we'll try to deliver it" or something clever like that.
You can connect to an mail server via telnet to ask whether an email address exists. MX preference = 10, mail exchanger = STACKOVERFLOW. It is used in production code in Zone Check except that it uses RSET instead of QUIT. Some server may not check the "rcpt to:" so is security risk.....
Greylisting: SMTP server refuses delivery the first time a previously unknown client connects, allows next time(s); this keeps some percentage of spambots out, while allowing legitimate use - About all you can do is search DNS and ensure the domain that is in the email address has an MX record, other than that there is no reliable way of dealing with this.