I have all of my domain mail delivered to a single ISP provided mailbox. I pull all of that with LANSuite and it puts it in the correct mailbox for each of the six accounts with the administrators being the catchall.
Currently, I have Zimbra being the front-end of the solution by each individual setting up their account and polling LANSuite for their mail. I would like to eliminate the LANSuite server and have Zimbra pull the mail from the ISP mailbox and distribute accordingly.
My DNS is hosted by my ISP and they won't point my MX at my server, they will simply direct it to a multidrop mailbox.
I also do not have a public static IP and have not had much luck with DynDNS in the past.
Do you have a paid-for domain name? If so, you should be able to host that anywhere. If you can move your DNS records then I'd recommend using EasyDNS for hosting those records, they also cope with dynamic DNS records and they have a backup mail server facility that will store your mail for up-to five days if your connection is unavailable. You could still relay via your ISP to get around any RBL lists that think your may be a spammer because you're on a dynamic DNS. Receiving your mail directly is by far the preferred solution.
Failing the change of DNS hosting, the only solution I know of for multi-drop mailboxes is fetchmail (there may be others). I've never used fetchmail for that function but it should work, the documentation is here. Please note the information about the problems you may encounter.
I am looking into both of them and will hopefully find a solution that suits my situation.
I have found one other product that will get the mail for you but unfortunately it's no longer developed. If you want to look at it then it's on Sourceforge and it's called TrestleMail, it might be worth a try if fetchmail doesn't do what you want.
I have signed up with EasyDNS and am in the process of transferring the domain.
I have a couple of newb questions, though. Once I have setup the MX record as a host on my system (MX record and A record), do I simply need to forward TCP 25 to the Zimbra server at the firewall assuming I do not want to use POP3 externally?
All of my hosts will have the same external IP so I would forward the relevant ports to the proper hosts.
What if my ISP is blocking 25? I don't know that they are but in the past I have used a non-standard port and wouldn't mind continuing to do so. EasyDNS did not allow me to specify a port although my current domain forwarder does.
Excellent suggestion on the EasyDNS. They are Canadian to boot...
I now have full DNS service with quick helpful tech support and it is nearly 50% cheaper than the crap service I had with Telus.
It is all working very well now and I will soon be asking stupid questions about more advanced features...
Like integrating my Asterisk server. 8^)