Activities

November 2012
M T W T F S S
« Oct   Dec »
 1234
567891011
12131415161718
19202122232425
2627282930  

Verifying the Email server reputation : RDNS, SPF and DKIM Keys

Recently I’d setup a bulk email server using Postfix MTA and optimize the postfix variables for huge email delivery. I uses sql based database for storing smtp logins. So that we can use this server to send bulk email from anywhere like smtp.com does. My Major setup including the following area,

1. SQL based user logins
2. Webmail and Awstats setup for initial testing [ these are optional and access is limited to IP]
3. Enable SMTP authentication
4. Domain setup : RDNS, SPF and DKIM Keys
5. Tools used : qshape ( perl open source script) for verifying email statistics)
6. VERT technology for managing bounced back emails

Here is some description to how to prepare email content to reduce the spam score

a. How to test RDNS is correctly configured.

You can use host < IP > name to verify it. Here is an example

 [root@rc-025 ~]# host 227.125.63.181
227.125.63.181.in-addr.arpa domain name pointer mail03.mydomain.com.
[root@rc-025 ~]#

b. How to verify SPF records setup

You can use dig command to do this “dig +short txt domain.com”

 [root@rc-025 ~]# dig +short txt  mydomain.com
"v=spf1 a mx ptr ip4:227.125.63.181 mx:mail01.mydomain.com mx:227.125.63.182 mx:227.125.63.183 mx:227.125.63.18 mx:mail02.mydomain.com mx:mail03.mydomain.com ~all"
[root@rc-025 ~]#

c. How to verify the DKIM key installed

 [root@rc-009 ~]# dig +short TXT default._domainkey.domain.com
"v=DKIM1\; k=rsa\; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDJ6ylHVjj8mucMzBZkqJ2ZHhCVrjezwuNsWNUV7kER+RDR338hstN2sb32jbSFVTyQ2p/GFraAdJqYDmZQGYTjzjVYY8DZcrqSpROw+HN8IwopPufI0wzgj6dJQK/iCkVHxpa7DGImsKQIDAQAB"

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>