A well dated argument this one, when retrieving e-mail from a mail server which protocol is best used?
I’ve been a long standing user of POP3, as many others. The reason this protocol is great is because it allows several devices the ability to download all e-mail messages within a retention period (most e-mail clients call this “Leave messages on the server for x days” in their settings). Storage requirements on the server are kept to a minimum and so is network load.
These reasons made POP3 the protocol of choice, at least in 1996 which is roughly the last time I looked at the issue.
IMAP however stores all messages on the server. Clients either browse the data available on the server, or synchronize with the server so they keep a copy of the same data. As storage is handled by the server, any message sorting on one device applies to all devices and marking of read or unread will also carry across to all devices – as each device is simply viewing data from the IMAP server.
Today computers are readily available and many have a collection of e-mail capable devices (I use 3 myself). Also we live in the era of Internet video so bandwidth and storage in a datacentre is both plentiful and cheap. Processors have probably seen the biggest expansion in cheap availability.
So earlier this year I migrated from POP3 to IMAP. Eventually I uploaded about a decade of old e-mails to my IMAP server. Using ZFS and Courier-IMAP-SSL over two nodes at the server end, I’ve ensured that I have high availability for my e-mail service.
Probably the biggest plus to using IMAP was backups. I already use bacula on my Linux based servers for daily off-site backups and this includes everything in /home. So without any change all my e-mail is backed up and stored off site every day.
Finally using GO Contact Sync Mod and Google Calendar Sync to keep my Microsoft Outlook contacts and calendar in sync with my Android phone – there really is no need to backup anything related to my e-mail at the client end on any computer because everything is either stored with the IMAP server or Google.