4 ms·

>They do this by literally sending the people an email. If it does not bounce, the email is validated. That's a pretty dumb way to validate an email address. Y

>They do this by literally sending the people an email. If it does not bounce, the email is validated. That's a pretty dumb way to validate an email address. You can just end the connection after a successful RCPT TO and no one needs to be the wiser. The method causes a false validation in the case of an intermediate mail relay that accepts everything but that is such a bad idea that no one does that.

samrohn 8y ago
catch-all domains cannot be validated this way. The only way(wrong) to verify them is to send a real mail and see if it bounces.
- chaosprophet 8y ago
  Actually a lot of email addresses cannot be validated this way since most ESPs including gmail have adopted an 'accept-all' approach to incoming email. So getting the email accepted by the server is no indication that the address exists, or that the email will actually be delivered to that address even if it exists.
  - upofadown 8y ago
    >... including gmail ... #> swaks --quit-after RCPT --TO kdskr3j2@gmail.com === Trying gmail-smtp-in.l.google.com:25... === Connected to gmail-smtp-in.l.google.com. <- 220 mx.google.com ESMTP a199si3828494itd.133 - gsmtp -> EHLO example.com <- 250-mx.google.com at your service, [xx.xx.xx.xx] <- 250-SIZE 157286400 <- 250-8BITMIME <- 250-STARTTLS <- 250-ENHANCEDSTATUSCODES <- 250-PIPELINING <- 250-CHUNKING <- 250 SMTPUTF8 -> MAIL FROM:<bob@example.com> <- 250 2.1.0 OK a199si3828494itd.133 - gsmtp -> RCPT TO:<kdskr3j2@gmail.com> <** 550-5.1.1 The email account that you tried to reach does not exist. Please try <** 550-5.1.1 double-checking the recipient's email address for typos or <** 550-5.1.1 unnecessary spaces. Learn more at <** 550 5.1.1 https://support.google.com/mail/?p=NoSuchUser a199si3828494itd.133 - gsmtp -> QUIT <- 221 2.0.0 closing connection a199si3828494itd.133 - gsmtp === Connection closed with remote host.
nerdbaggy 8y ago
Most major email providers will block your IP from doing this a lot

samrohn 8y ago

catch-all domains cannot be validated this way. The only way(wrong) to verify them is to send a real mail and see if it bounces.

chaosprophet 8y ago
Actually a lot of email addresses cannot be validated this way since most ESPs including gmail have adopted an 'accept-all' approach to incoming email. So getting the email accepted by the server is no indication that the address exists, or that the email will actually be delivered to that address even if it exists.
- upofadown 8y ago
  >... including gmail ... #> swaks --quit-after RCPT --TO kdskr3j2@gmail.com === Trying gmail-smtp-in.l.google.com:25... === Connected to gmail-smtp-in.l.google.com. <- 220 mx.google.com ESMTP a199si3828494itd.133 - gsmtp -> EHLO example.com <- 250-mx.google.com at your service, [xx.xx.xx.xx] <- 250-SIZE 157286400 <- 250-8BITMIME <- 250-STARTTLS <- 250-ENHANCEDSTATUSCODES <- 250-PIPELINING <- 250-CHUNKING <- 250 SMTPUTF8 -> MAIL FROM:<bob@example.com> <- 250 2.1.0 OK a199si3828494itd.133 - gsmtp -> RCPT TO:<kdskr3j2@gmail.com> <** 550-5.1.1 The email account that you tried to reach does not exist. Please try <** 550-5.1.1 double-checking the recipient's email address for typos or <** 550-5.1.1 unnecessary spaces. Learn more at <** 550 5.1.1 https://support.google.com/mail/?p=NoSuchUser a199si3828494itd.133 - gsmtp -> QUIT <- 221 2.0.0 closing connection a199si3828494itd.133 - gsmtp === Connection closed with remote host.

nerdbaggy 8y ago

Most major email providers will block your IP from doing this a lot