Due largely to some complicated housemate-changing, we've recently had utility-based turmoil. That's mostly sorted out now, and we've ended up on O2 broadband. Hey ho. I've nothing to complain about yet, at least in terms of the service, but I did have to spend a while digging up server settings for Thunderbird from all across the web. So I'll repost them here in case they help anyone.
As of today, the settings that work on Thunderbird 15 for Tools > Account Settings > Outgoing Server (SMTP) are:
- server name: smtp.o2.co.uk
- port: 25 (587 did not work, regardless of some comments elsewhere)
- security: none (seriously, O2? not impressed)
- authentication method: password, transmitted insecurely
- user name: YOURUSERNAME@o2.co.uk
Despite what some comments and the O2 website seem to suggest, you do not need an O2 email address to set this up. I was using a straightforward username to log into the O2 website; it currently invites you to use an email address instead, but I told it to skip that. Simply take whatever username you use to log into O2, which you set up while ordering the service, and which you can retrieve via a link in their emails. Use that username with @o2.co.uk as the user name. The password is the one for that login.