Changed 2023-12-29 early hours.
Reasons for having it on a special URL: Hoping to reduce automated login attempts by making it fairly invisible to the uninitiated. And by using a different name from ntmm.org/mail or mail.ntmm.org we make it easy to change where we run the webmail, without having to change the main webserver or the mail settings for mail-clients.
Please check the configuration options. You might prefer the classic interface to the default one; or having the mails-list and preview-pane side-by-side rather than one over the other; or having a new browser window for viewing or editing mails, etc.
It might be that you need to subscribe to subfolders, if you only see the Inbox. This simply means going to Folders settings and checkbox-ticking all the folders you want to appear.
Examples of mail clients: Thunderbird, perhaps still Opera?
Could also be alternative webmail providers that can pretend to be a mail client for connecting to other email servers.
Using such a "real" mail client is generally nicer when working with loads of mails, moving between boxes, trying to archive things, etc.
If you're just updating the account settings, you might find that the silly thing wants to restart a couple of times because you've changed the server or username, and that you need to check that it's going to put Sent mails into Sent on the server (instead of reverting to putting them on the local computer, which usually isn't what you'd want). Just have a good check through the settings and account settings after updating the server settings.
For viewing/sorting/etc the mails that you've received on ntmm.org:
Note! ... at least for my use-case, it's important to tell thunderbird that it should not try to download and locally store all the mails – I've got 15 GB of mails in multiple folders, so this annoying default behaviour makes Thunderbird very slow. Under "Settings", "General", "Network & Disk Space", I set it to override automatic choices and limit downloads to a few tens of MB. Likewise under "Account Settings", (account name), "Synchronisation & Storage" I set to just the most recent day and a size limit.
Of course, if you have a modest number of mails, or use Thunderbird on only one computer, then it could make good sense to have a complete download of a local copy, which would only need to update new mails each time you connect, and could be a useful backup.
Beware also of any setting that would cause the mails on the server to be removed after some time or after downloading – it's probably not what you want.
For sending mails via ntmm.org:
It should now be possible – though inadvisable – to send obscenely large attachments even in the webmail. The webmail claims 75 MB. I think I made the mailserver itself tolerate the >100 MB range.
That doesn't mean you should make use of this ability: it's common that servers "at the other end" won't accept more than a few tens of MB. That's already been shown when I tried to send ~55 MB to my work address (it appeared to be accepted from our mailserver, but it didn't arrive). According to one result from a quick search (not entirely clear whether it's about limits for receiving) very few major providers tolerate more than 25 MB, and there are some with a limit at 20 MB, and a case or two with 10 MB. Perhaps the only purpose of the obscene sizes is for files between ourselves, for which we probably should be able to find a better way, though sometimes it's nice to have emails for the archive.
Note that email attachments take more MB of email than their actual size, by a factor 8/6, because each 8-bit byte within the mail, though able to represent 256 (28) different values, is used to represent one of just 64 (26) printable characters in order to pass through a channel designed for text. So there can sometimes be a confusion about whether a limit means the attachment itself or the email containing it.
In contrast to the earlier setups, we now have properly signed SSL certificates for all the services (web, imap, smtp). So there shouldn't be any case of "Insecure", "Do you want to proceed", "Make an exception?", "Warning: Go back", etc.
Thank you to https://letsencrypt.org/ for this very well-functioning certificate-signing service. Please complain at me if ever there's an expiry warning (every 90 days I have to renew it).
We can consider having SquirrelMail if users loathe Roundcubes. Roundcube appeared more established nowadays in things (e.g. RedHat Enterprise Linux) that cater for long-term service and big sites, though I see the SquirrelMail is still getting development work, thus not abandoned. Although I haven't seen (!) signs of security trouble with our earlier setup, which ran Squirrel, Roundcube and Hastymail for some five or more years without update and on an expired system, I'm trying to be better with the new system: as few entry-points as possible, and with updates (hence update-work increases with number of things).
Initially we're sending outgoing mail directly from the home computer. That's worked for the cases I've tested so far. The possible problem is that it doesn't "look quite as good" as my work computer: it's clearly an ISP address rather than a fixed university one, and it hasn't got DNS records that match in both directions between the name and the address. So, although ntmm.org lists it as a permitted outgoing server, some more fussy services or spam-filters might inflict their prejudices on mails that it delivers or tries to deliver. If we have troubles, I'll change to tunnelling via work.
You probably have (by agreement with me) multiple "aliases" that all come to your one Inbox. Indeed, most users have an alias as their intended "main, official address": my actual account is ntm@ntmm.org (ntm means 'NT mail'), but I use my full name @ntmm.org as the main email, and then come aliases such as nauttruk@ntmm.org [which I gave to autotrader.co.uk] etc.
Thus, the login name is short, and the main mail address is "friendly". The extra aliases are a way to limit the annoyance when addresses get given to (or taken by) spammers: fine-grained use of aliases allows the bad one to be discarded without side-effects.
I have to set up the aliases in order for mails to them to be received: you can't just invent one any time you feel like it. But you can have a selection set up in case they're wanted. You'll receive the mails sent to them, even if you haven't set up any reference to these aliases in your webmail or mail-client. If you want to send from an alias (so that the recipient sees the aliase and not your main address), you may need to set up an Identity in the webmail or mail-client. The case in which this isn't needed is when using a client (e.g. Thunderbird) that has an option for specifying an arbitrary From-address at the time of sending. In Thunderbird this is "Customize From address" in the drop-down list of "From" options in an "Edit mail" window.
The outgoing mailserver (through webmail or a mail-client) is set up to accept sending from any claimed email address. That's because we've only a few users, they're trusted, all have one or more aliases, and some have email accounts in other domains that they might want to use sometimes as the sender address in our system.
If you're using aliases at ntmm.org there should be no problem, except that if I haven't included the alias in the server's list then it's not going to accept any incoming replies to your mail. Ask me if you want the list of all your aliases.
If you claim to be in another domain (e.g. sending through our service, with From address 'a_name@something.com') there's a chance the mail will be rejected by the recipient's server because of "SPF" (sender policy framework). SPF is a way of publishing a list of which computers are allowed to send mail for a domain. If you control the domain's DNS and have an SPF record, you can add +a:serv.ntmm.org/32 +a:gnu.ntmm.org/32 to its SPF list to allow our servers.
I try to keep things safe by having some redundancy of the disks and some backup copies, but you must take your own copies if data preservation is critical for you. The previous computer is an example of how I've been too busy to bother fixing a could-fail-any-time-and-now-down-to-no-redundancy-in-the-disks computer.
If you want backup, your mail-client (or perhaps the webmail ... not sure!) can possibly do something useful, for letting you dump multiple mails as some sort of local file on your computer.
If you have SSH access to the server, you could use rsync or similar to copy ~/Maildir/ (all the emails) or parts thereof. Mail-users in general don't have SSH access: I prefer to keep login and mail accounts separate, except in special cases. We could sort out a login for frequent use, or I can give you an archive of mails occasionally.