[Python] python: correct method verify if email exists

I am trying to verify if an email actually exists by first resolving its dns, then check if the email is valid using the below code:

email = test@cisco.com
domain = email.split("@")[-1]
records = dns.resolver.query(domain, 'MX')
mxRecord = records[0].exchange
mxRecord = str(mxRecord)
server.connect(mxRecord)
server.helo(host)
server.mail('myemail@gmail.com')
code, message = server.rcpt(str(email))
server.quit()
if code == 250:
print('valid email', message)
else:
print('invalid email', message)


This works few times, but when I send multiple request I get a message like:

"5.7.1 Service unavailable, Client host [122.166.xxx.xxx] blocked using Spamhaus. To request removal from this list see http://www.spamhaus.org/lookup.lasso (AS160312312) [BL2NAM02FT12312.eop-nam02.prod.protection.outlook.com]'"
​

I understand that they are trying to block my ip address as it thinks its spammy.

Here are my questions:

• Is there a right way to do this type of email validation, without getting marked as spam? Is it getting marked as spam as I am running the code on my system and just giving a dummy value for email like

server.mail('myemail@gmail.com')
​

• Is it possible to use some proxy to do this? My usecase require 100's of email addresses to be verified. I see some commercial api available for email validation, but it is not feasible for me at the moment.

Continue reading...