Email Validation and Reverse-validation Methods – Self hosted email servers

Email Validation and Reverse-validation Methods – Self hosted email servers

September 19th, 2015 // 6:08 pm @ Arad Gharagozli

If you are using your own mail server and have heard people complain that your emails (emails that are coming out of your mailserver) is getting marked as spam, or junk, you are not alone. Here is few things to do

IP Blacklist

Sometimes, due to low or no security measures, spammers can hook to your mail server, and start sending out lots and lots of spams. In that case your server’s public IP will be marked as spam, and every email out of your server will be marked spam as well.

See this site to check your IP status, and take the necessary measure if it wasBlacklisted

http://mxtoolbox.com/blacklists.aspx

OR

http://www.blacklistalert.org/

SPF Fail

In case you haven’t specified SPF (Sender Policy Framework) for your domain, your emails will be marked as spam. SPF is a mechanism that matches the senders IP address to the IP address residing in the mail’s header. So you can see if the sender is actually who they claim to be

Check this link for your current SPF record: mxtoolbox.com/spf.aspx

How add SPF Record

SPF is simply a DNS record in a form of TXT . so simply:

1. Under your hosts control panel find where to create/edit DNS Zones
2. Create a new DNS/Zone entry (Add a new Zone)
3. New zone’s setting:
   1. Type: TXT
   2. Name: should match your email’s domain name(me@example.com > example.com)
   3. TTL: 3600 or 14400 (either would do)
   4. TXT Data: [See the text below for full info]
4. After adding all the info sae and give it a day to fully broadcast

TXT Data for Zone entry

TXT Data is the most important part You can use this online tool to create your TXT DATA and copy/paste it to the field we talked above:   http://spfwizard.com/

Your overal should look something like:

v=spf1 mx ip4:12.34.56.78 ?all

Where (12.34.56.78) is the public IP address of your mail server.

NOTE: Be careful, if your mail server sends out email under different hosts you need to have that host added

Example:

I have an automated code that sends out email as auto-respond@security.com , although the email address is auto-respond@security.com, the recipient’s server sees it as exchange.arad.me as opposed to SOME-SERVER.security.com

The best way to find this is to send an email, from the affected address to your gmail, or yahoo. Then you can use the detail feature to see the details of the delivered message by Google or Yahoo and see what they actual server name and IP is. Then include those domain names and IP addresses in your SPF record to ensure full authenticity.

 

For cPanel Users

If you are a cPanel user, then your in luck. cPanel has a fantastic tool that would take care of your SPF needs, and it’s called “Authentication” , and you can find it under “Email” section.

When you enter Authentication, you will see DKIM (for incoming messages) and SPF. Simply, ENABLE the SPF and it will populate your Zone Records

Category : Common Techniques &Tricks