DNS Woes and Email Confusion

[artisticdigital]

I would like some confirmation on the following setup and trying to figure out whats going on with our emails. Here is the current setup.

Hostname

eth0:1 - jas.abc.com - 6x.xx.xx.194 - Reverse Lookup: jas.abc.com = 6x.xx.xx.194

We have four NIC's installed on this server, here are there configurations

eth0 - ns4.abc.com -6x.xx.xx.193 - Reverse Lookup: ns4.abc.com = 6x.xx.xx.193
eth2 - ns1.abc.com -6x.xx.xx.190 - Reverse Lookup: ns1.abc.com = 6x.xx.xx.190
eth3 - ns2.abc.com -6x.xx.xx.191 - Reverse Lookup: ns2.abc.com = 6x.xx.xx.191
eth1 - ns3.abc.com -6x.xx.xx.192 - Reverse Lookup: ns3.abc.com = 6x.xx.xx.192

The problem we are currently having is with high level companies not recieiving some email. As an example about 80% of emails make it through to comcast and aol but 20% of them remain stuck in my queue in till they time out. The strange thing is that about 80% of our emails leave the server but there is always 50 - 60 legitimate emails stuck that I can not get to send out. This are valid email accounts they are being attempted to be send to. This is a pretty urgent matter as important email is not getting delivered in a timely manner.

I think what is happening is the qmail is using eth0 so the email headers look like the email is coming from ns4.abc.com not jas.abc.com and the HELO is jas.abc.com. Please let me know if more info is needed, or any suggestions.

Example Header

RECEIVED: from ns4.abc.com (HELO jas.abc.com) (6x.xx.xx.192)

 

[hardweb]

Qmail answers with a single hostname.
On an IP you can have a single reverse name.
Qmail sends emails from the first IP on the server.

So, if you host multiple domains technically anyone can reject emails because you can not solve the issues above. If you host a single domain, of course that it will be ok.