Topic: Master / Slave servers

[dehacked]

I have a number of geographically disperse offices that get emails from my server. Due to intermittent connectivity issues I'm playing with the idea of putting a slave server in each of these locations so that users will at least perceive the mails to be working all the time. There is resilience in the network but limited automation so the idea is for the servers to catch up as soon as connectivity is manually restored. Not ideal, but this is Africa... I recall I saw SME having this ability some time back but I'm not able to find the documents. Am I mistaken or can someone please point me in the right direction?

[nicolatiana]

The first and simple idea is local Sme servers with fetchmail downloading mail from the main server (every 15', for example) and local clients getting mail from local servers via IMAP. Valid for both xDSL or dialup (dialup needs a server&gateway configuration and a RS232-not-pci modem).

http://wiki.contribs.org/SME_Server:Documentation:Administration_Manual:Chapter5#Configuring_the_Server_for_Server_and_Gateway_Mode_-_Dialup_Access

Nicola

[janet]

dehacked

I am not aware of any Master/Slave setups. You may be referring to the high availability howto from years ago, or perhaps the current LDAP implementation in sme8.

You can create standalone mail servers (based on sme) at each location.
Configure them with their own domain eg office1domain.com, office2domain.com, or a subset of your main domain eg office1.mydomain.com, office2.mydomain.com etc, or use free domains from dyndns etc.
On the main server you could have forwarding setup to deliver the main domain email to the subdomain mail servers eg user1@mydomain forwards to user1@mydomain (local), user2@mydomain forwards to user2@office2mydomain.com (remote) & so on. That way users can retain their original user@mydomain addresses, but of course all messages will be routed through the main server. Alternatively send direct to the subdomains, and rely on mail servers (external) to queue the messages for a few days.

Then just allow qmail to deliver the messages when the servers come on line. Qmail will keep trying for 7 days, before sending an undeliverable message to the sender.
Avoid fetchmail as much as possible.