Some problems here with being IP getting permanently blocked from the big boys since switching from sendmail/spamassassin/procmail/qpopper/poprelayd/squirrelmail to iRedMail

I installed iRedMail back in October/November on this server and for the year prior had no issues with mail. I Jan I flipped the switch from sendmail/qpopper to use iRedMail. Within 2 weeks we were blocked and from contacting AOL, Hotmail, Live, Comcast, Bellsouth, and Yahoo my IP has been permanently blocked. They do not even bounce emails thus I get no errors returned. Its just a connection refused - IP permentally blocked as I see in the mail logs.  I have worked with all of them to get removed and as soon as they remove I get permanently blocked again. I cannot figure out what in the install/setup would cause this to happening and there are no specifics from the blocking providers other than they release blocking and it gets blocked again.  I have had to out source the email for myself and my clients but of course any web site generated emails are still blocked causing havock for some importants clients such as a CA DMV online traffic school, a 1.2 million appliance part ecommerce system and my own golf web sites that generates the majority of our operating revenue which offsets a lot of the charity work we do. Fortunately we are off season so it hasn't impacted our operations yet but this needs to be rectified before season starts.

There are only 3 account users on my server. Myself and 2 others of which are highly trusted and respectable users and I view the log watch report daily.  No one is spamming or sending out overlimit emails to these providers. I have postmaster accounts with yahoo, live and AOL and never get any reports. The ip and domain names are clean on all blacklists including the dreaded sorbs.

I have just set up DKIM and SPF hoping this might help in the issue and those records show in the mail headers properly for each domain sending (although the headers still reflect the outgoing mail as from the server host name and not as the DKIM sig domain name so there is this new descrepancy (see another post earlier asking for help)

I am trying to change the IP for the mail aspect of the server but do not know all of the config files required to run iRedMail from a different bound ip/host on the server. See earlier Post.

What in the default installation from Oct 2009 would be causing the mail system to get blocked by all of the big boys?

Please help shed some light on this issue.

Thank you,

Richard