Is it possible to relay mail this way?

[CdtDelta]

Hey all,
Ok, another n00b question, I've been trying to get this working all day. So here's how my mail is setup. I have a domain with a hosting company, say mydomain.com. So when mail is sent to me@mydomain.com, my hosting company forwards that email to my mail server on my local network. So if you do an MX lookup for mydomain.com it points to my hosting company's mail server not my Zimbra server on my home network (which is the way I want it).
So my mydomain.com mail I want to flow through my home Zimbra server, but I don't want the MX record to point to my home network IP.
Is there a way to actually accomplish this? Or do I have to change the MX record for my domain to point to my home network IP (which I would rather not do if I don't have to).
I'm running Ubuntu 6.06 LTS and the 5.0 RC2 Zimbra server.

Thanks, ahead of time....

[dijichi2]

couple of workarounds I can think for this. one is to use another domain name (or subdomain - eg. home.mydomain.com) and set the mx of that domain to your home IP (hope it's static otherwise it's more tricky. if it is dynamic, use a service such as dyndns.org and point to that address - don't point to a cname). then configure that domain or subdomain on your home zimbra server and forward to that address. you can also configure your main mydomain.com on your home zimbra if you want to send out as this address for instance, and alias your other domain or subdomain onto your main domain just for delivery.

[CdtDelta]

Well I have a static IP on my home network, so that's not a problem. But I wasn't clear about what your second workaround was.
The problem I'm dealing with is if I enable DNS lookups, I can send mail out, but not receive mail in. If I disable DNS lookups, I can receive mail but not send it (using the setup that I want).
If I enable DNS lookups, the issue is when mail comes in, it does a DNS lookup of my Zimbra server, and the DNS servers it's using for the lookup give it the wrong IP (because it's an internal server without an external IP address).

[dijichi2]

well you need to do either one of two things:

1) setup split-horizon dns to resolve your local addresses

2) put your internal server hostname/ip address into public dns, and alias the public hostname.