Multiple sites sending mail using SMTP IIS6

We host five sites from the same server with each site technically belonging
to a different domain. For example...

www.site1.com
www.site2.com
www.site3.com
www.site4.com
www.site5.com

Each site has its own dedicated external and internal IP address. On the
firewall I simply setup a NAT so that X.X.X.1 goes to its appropriate
internal IP, X.X.X.2 goes to its appropriate internal IP, etc. I do this so
that I do not have to rely on the parsing of the host header information.

What I'm wanting to do now is use SMTP within IIS to facilitate email for
each site; however, it's imperative that this email traffic pass reverse DNS
checks. I would like to setup A records for each domain such as
mail.site1.com, mail.site2.com, etc. I would also like for email for each
domain to use a different external IP address when sending out.

Is this scenario possible with an instance of SMTP in IIS 6?

I hope I worded this correctly.

Thanks in advance.

RE: Multiple sites sending mail using SMTP IIS6

Perhaps I should have done a little more research...I think the answer to
this problem would be to create a virtual SMTP server for each site and
assign each virtual SMTP server its own internal IP address. Then on my
firewall I can create NAT rules to map each virtual SMTP server to its own
external IP address.

Thoughts?

"Steven Woods" wrote:

> We host five sites from the same server with each site technically belonging
> to a different domain. For example...
>
> www.site1.com
> www.site2.com
> www.site3.com
> www.site4.com
> www.site5.com
>
> Each site has its own dedicated external and internal IP address. On the
> firewall I simply setup a NAT so that X.X.X.1 goes to its appropriate
> internal IP, X.X.X.2 goes to its appropriate internal IP, etc. I do this so
> that I do not have to rely on the parsing of the host header information.
>
> What I'm wanting to do now is use SMTP within IIS to facilitate email for
> each site; however, it's imperative that this email traffic pass reverse DNS
> checks. I would like to setup A records for each domain such as
> mail.site1.com, mail.site2.com, etc. I would also like for email for each
> domain to use a different external IP address when sending out.
>
> Is this scenario possible with an instance of SMTP in IIS 6?
>
> I hope I worded this correctly.
>
> Thanks in advance.