How do I fix the Reverse DNS entry(ies)?

Hello,folk!

I'll be as brief as possible:

Our servers and all client systems are on private IP subnet inside the
firewall (Pix).
Back in the summer we moved to Exchange 2003 and found we couldn't mail to
aol.
I found out it was because of the server's reverse dns entry being in error
or missing, so I had the ISP correct that and all was well.

Now.. we recently installed an anti-spam device (Barracuda) inside our
firewall. All inbound mail is routed from the firewall to the Barracuda,
then the Barracuda forwards to our Exchange 2003 server. Outbound mail goes
directly from our Exchange server with no involvement from the Barracuda.
However... we are once again unable to send mail to aol and I'm guessing
that the reverse lookup process is hosed since we installed the Barracuda
and are using the same external (Internet) IP as we were on the Exchange
server. I know I need to contact the folks that host our dns to get this
corrected, but I'm not sure what entries I need to request. Do I create a
new MX and PTR records for the Barracuda (cuda.x.com) and point them to the
same Internet-IP as our mail server (mail.x.com)? Remember outbound mail is
still flowing direct from Exchange.

I'm just a little foggy on how the reverse dns lookup would work in this
case and how to straighten it out. ANY input is very welcome!

Thanks,
Bill

Bill,

We have a similar scenaro and we opted to ask the ISP to allow us to router
outgoing mail thru them. And in our Exchange I set them up as a smart host
and that fixed all of our problems.

--
Devin M.
Network Engineer
Digital Planet
Detroit, MI.


"Bill" wrote:

> Hello,folk!
>
> I'll be as brief as possible:
>
> Our servers and all client systems are on private IP subnet inside the
> firewall (Pix).
> Back in the summer we moved to Exchange 2003 and found we couldn't mail to
> aol.
> I found out it was because of the server's reverse dns entry being in error
> or missing, so I had the ISP correct that and all was well.
>
> Now.. we recently installed an anti-spam device (Barracuda) inside our
> firewall. All inbound mail is routed from the firewall to the Barracuda,
> then the Barracuda forwards to our Exchange 2003 server. Outbound mail goes
> directly from our Exchange server with no involvement from the Barracuda.
> However... we are once again unable to send mail to aol and I'm guessing
> that the reverse lookup process is hosed since we installed the Barracuda
> and are using the same external (Internet) IP as we were on the Exchange
> server. I know I need to contact the folks that host our dns to get this
> corrected, but I'm not sure what entries I need to request. Do I create a
> new MX and PTR records for the Barracuda (cuda.x.com) and point them to the
> same Internet-IP as our mail server (mail.x.com)? Remember outbound mail is
> still flowing direct from Exchange.
>
> I'm just a little foggy on how the reverse dns lookup would work in this
> case and how to straighten it out. ANY input is very welcome!
>
> Thanks,
> Bill
>
>
>