Our Email Filter

In order to combat the ever increasing spam epidemic we have deployed several validation measures in our email system, and as is the nature when fighting spam, legitimate emails could get blocked too.

We have kept our email validation model in line with several of the larger email providers, so any changes you have to make to ensure email is delivered correctly to ComponentSource will benefit you further, as more and more companies take up these measures.

The following is a technical insight into the preventative measures we take and how you can avoid your emails being rejected by our servers. It is written for someone who is experienced with networking services and protocols such as DNS, SMTP and TCP/IP.

Reverse DNS Lookup

This checks that the connecting IP Address of your mail server has a reverse DNS entry for the connecting Hostname of your mail server. Using “reverse dns test” in an internet search engine will bring back many results that can help you test your configuration, you will need to know the IP Address of your sending mail server and it’s fully qualified hostname to use these tools successfully.

You may need to speak to your ISP to get reverse DNS for your IP range delegated to whichever servers are responsible for your DNS.

HELO/EHLO Hostname

When your mail server communicates with the ComponentSource mail server it identifies itself using a HELO or EHLO statement, the ComponentSource mail server would provide the following;

  • HELO mail.componentsource.com

The hostname specified after the HELO or EHLO is validated against the hostname retrieved from the Reverse DNS Lookup.

This HELO / EHLO statement will be a setting in your mail server configuration.

Domain Name DNS

We will validate that your sending domain exists and has DNS records associated with it, this is to stop spammers using invalid domains. Assuming your sending domain is registered with an ISP and they, or yourselves are responsible for the DNS this should not cause an issue.

If you have confirmed your setup against all these steps and you still believe your email is not getting through, please contact us using one of our toll free numbers, listed on our contact us page, and someone will gladly assist you.