Verify email addresses is a difficult and long road


New Member
I bought Mailwizz last month, and I started my email marketing in recent days.
First I use Mailgun and Amazon SES as my email sender.

Yes, you guessed it I was blocked by Mailgun and got a warning of bounce rate through Amazon ses. and my emails bounce rate around 10%.

I started to find a tool to verify my email address, I found bulkemailchecker,, verifyemailaddress and so on, but their price is a little high,I will pay 1k for my 5m emails if I use one.

This price exceeds my imagination, I think $1/10k maybe the most reasonable price.
I decided not to use them.
I am a programmer and I only need to find the process' path of the program,I can create one.

I found it last week, this program is so old and it uses smtp mail from and rcpt to check users, it is very dangerous but it is the best way.

I fixed the program and started to run, the program runs perfectly in first hour, and it verify about 10k emails,but later I found only half of it was right, the last 5000 was false.

I debug the program and I found out that my IP was blocked, the program runs and I got correct verify after I changed my IP address.

Just now I found almost of VPS ip addresses was in RBL(like Digitalocean), and the mail server use them to prevent the connection immediately if use it.

I need to find a new solution to make my program continue to run...


Well-Known Member
So what did your program check?
these programs run en empty email by the recipient mta to see if the email add is OK

many mta don't like too many connections, so you get blacklisted

and local programs without rdns are not working for long if at all
hence you need to go slowly and randomly and have a server/ip farm, etc