ESN . POSTMASTER

Extra Security Networks


Frequently Asked Questions

Does ESN provide a feedback loop?
Not at this time. Please refer to the SMTP error message, to find the specific reason that your email was rejected.

I'm not a spammer, so why do you reject email from my server?
There are many reasons why a specific email may be rejected. But most emails are rejected due to poorly configured sending servers. Here are a few reasons why your email could have been rejected, ordered from most frequent to least frequent.

  1. Lack of reverse DNS
  2. Dynamic or residential IP
  3. Invalid helo, or unable to resolve helo command
  4. Lack of FcrDNS
  5. Domain or mailbox unknown
  6. Local block lists
  7. Invalid sender address
  8. Third party block lists
  9. IP location
  10. Email content

Why does ESN reject all email from my country?
We do not block all of the email from your country. But we may subject IP addresses that were assigned in, or are located in certain geographic areas, to very strict tests.

However, the owners of specific mailboxes may decide that they will not accept mail from some countries, or decide to only accept mail from a few specific countries.

Does ESN use grey listing?
Some mailboxes do.

How do I get placed on the white list?
ESN does not whitelist any IP addresses. If you want to ensure delivery to mailboxes on our network,

  • Configure your mail server properly
  • Don't send spam or unsolicited email to mailboxes on our network
  • Stay off of third party block lists

Where can I test if my server is on a block list?
MX Toolbox provides several online tools for testing your mail server configuration.