(Objective-C) Verify Email Recipients

A way to possibly determine valid/invalid email addresses. I would recommend being very careful about doing this because your IP address may be flagged as a potential spammer by the mail server (because you are probing for valid/invalid email addresses). This Chilkat functionality existed for many years, before this kind of activity became a problem. The functionality remains only because it is useful for some to test with their own SMTP servers.

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#import <CkoMailMan.h>
#import <CkoEmail.h>
#import <CkoStringArray.h>

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoMailMan *mailman = [[CkoMailMan alloc] init];

// SMTP connection settings...
mailman.SmtpHost = @"smtp.example.com";
mailman.SmtpUsername = @"MY_SMTP_USERNAME";
mailman.SmtpPassword = @"MY_SMTP_PASSWORD";
mailman.SmtpSsl = YES;
mailman.SmtpPort = [NSNumber numberWithInt:465];

// Create a new email object
CkoEmail *email = [[CkoEmail alloc] init];

email.Subject = @"This is a test";
email.Body = @"This is a test";
email.From = @"myemail@example.com";
BOOL success = [email AddTo: @"person1" emailAddress: @"person1@example.com"];
success = [email AddTo: @"person2" emailAddress: @"person2@example.com"];
success = [email AddTo: @"person3" emailAddress: @"person3@example.com"];
// The SMTP server smtp.example.com won't know anything about an email address @somewhere_else.com
success = [email AddTo: @"person3" emailAddress: @"person4@somewhere_else.com"];
// ...

// Verify recipients.
// **** See the warning about using this API method in the description above.
// (An SMTP server only knows valid email address for its own domain.  For example,
// smtp.example.com *may* only know if person1@example.com is valid or invalid, but does
// not know anything about the validity of email addresses having other domains.)
CkoStringArray *badAddrs = [[CkoStringArray alloc] init];
success = [mailman VerifyRecips: email saBadAddrs: badAddrs];
if (success != YES) {
    NSLog(@"%@",mailman.LastErrorText);
    return;
}

int i = 0;
while (i < [badAddrs.Count intValue]) {
    NSLog(@"%@",[badAddrs GetString: [NSNumber numberWithInt: i]]);
    i = i + 1;
}

NSLog(@"%@",@"done.");