We have a MDaemon email sevrer hosting in our office in Vietnam using lease line 1.5Mbps. Inside Vietnam, our staff can access email without any problem but in some countries like Australia, HongKong and especially in USA they can't send/receive there mails or if yes, it's very very slow. We plan to have a second server somewhere outside Vietnam to let staff working abroad can check their mail from this second mail sevrer. Please help us how to synchronize 2 servers, how to setup that staff working from abroad can accsess the second server. Or if you have another solution for us.
Thanks.
You might consider an option like GOOGLE GMAIL for Business, your email is stored in google servers around the world, which are probably very fast to access in most countries. You can have you own domain and branded page (no gmail logo, etc).
As you told, you can also build a second mail server... which might be more expensive and might require a IT staff to manage it.
You can achieve this with: - Zimbra (Mirror Server) - Microsoft Exchange (Mirror Server)
Why not a solution like gmail? http://www.google.com/apps/intl/en/business/index.html
Option are google apps host your mail server on AWS using Postfix or Sendmail :)