Topic: running 2 instances of IRM as internal & external mail server
I have installed IRM (with an external LDAP server running GOsa, 1 domain only, let's call it example.com) and all works together very nicely. Now I am trying to do this: install 2 instances of IRM (referring to the same ldap server) as follows:
- one is external, has good connection to Internet and is always online. This servers as the primary MX for domain example.com
- one is placed inside the internal network, has slow connection to Internet and is switched on/off on a daily basis. This serves as the internal mail server.
- each user has email address in form email@example.com
- mails from Internet sent to @example.com are accepted and stored on the external server
- when the internal mail server is on, it keeps pulling mails from the external server, so that mails sent to @example.com are delivered to the internal mail server.
Can someone please suggest (very roughly) how to achieve the above?
I think one possible method is to use fetchmail or getmail to fetch mails let's say each 10min from the external server. But I could not figure out how to fetch all new mails for all users via a single account.