Update README.md

Added latest front page appearance of Mail-In-A-Box to README.md

Echange -> Exchange

Closes #413.

security.md: add links to appropriate source files in various places to make it easier to inspect the code to verify the statements; unfortunately line numbers will drift but it would be nice if we could link right to line numbers

after installing an SSL certificate from the control panel the page wasn't being refreshed, broken in ec73c171

Make SPF forbid any outbound mail from non-mail domains

Improve DMARC and SPF record descriptions

Unfortunately our users/aliases database is case sensitive. (Perhaps I should have defined the columns with COLLATE NOCASE, see https://www.sqlite.org/datatype3.html.) Postfix always queries the tables in lowecase, so mail delivery would fail if a user or alias were defined with any capital letters. It would have also been possible to add multiple euqivalent addresses into the database with different case.

This commit rejects new mail users that have capital letters and forces new aliases to lowecase. I prefer to reject rather than casefold user accounts so that the login credentials the user gave are exactly what goes into the database.

https://discourse.mailinabox.email/t/recipient-address-rejected-user-unknown-in-virtual-mailbox-table/512/4

Use lowercase h for consistency in aliases template - it reads better…

This also includes fixes for a typo and some whitespace inconsistencies in
mailconfig.py. In fact the capitalisation change and those fixes are the
remnants of a patch I had been running that changed the default aliases - it
was through developing it that I found the issues.

(I wanted to bring the number of patches I apply before deploying to zero and
in the case of this one I've come to view the way MIAB already is as superior,
so I've undone the core of my patch and these tiny issues are all that remain).

A lot of legit mail servers try again between 200 and 285 seconds, then
3 hours later. Why? RFC is not strict about retry timer so postfix and
other MTA have their own intervals. To fix the problem of receiving
these e-mail really latter, I reduced the delay of postgrey to
180 seconds (default is 300 seconds).

Fixing minor misspelling of the word: encrypted

The submission port began offering SSLv3.

With `encrypt`, the smtpd_tls_protocols option is ignored and smtpd_tls_mandatory_protocols must be set instead.

see e39b777a

Starting with my dnswl.org modifications to postgrey.

The OVH VPS provider creates systems without /dev/stdout. I have never seen that before. But fine. We were passing it as a command line option to `openssl req`, but outputting to stdout is the default so it's not necessary to specify /dev/stdout.

Fixes #277. Also https://discourse.mailinabox.email/t/500-internal-server-error/475/10.

if the main ssl cert is expiring soon, the end of setup would display the control panel instructions as if the cert were self-signed

see #375

=====

May 8, 2015

Mail:

* Spam checking is now performed on messages larger than the previous limit of 64KB.
* POP3S is now enabled (port 995).
* Roundcube is updated to version 1.1.1.
* Minor security improvements (more mail headers with user agent info are anonymized; crypto settings were tightened).

ownCloud:

* Downloading files you uploaded to ownCloud broke because of a change in ownCloud 8.

DNS:

* Internationalized Domain Names (IDNs) should now work in email. If you had custom DNS or custom web settings for internationalized domains, check that they are still working.
* It is now possible to set multiple TXT and other types of records on the same domain in the control panel.
* The custom DNS API was completely rewritten to support setting multiple records of the same type on a domain. Any existing client code using the DNS API will have to be rewritten. (Existing code will just get 404s back.)
* On some systems the `nsd` service failed to start if network inferfaces were not ready.

System / Control Panel:

* In order to guard against misconfiguration that can lead to domain control validation hijacking, email addresses that begin with admin, administrator, postmaster, hostmaster, and webmaster can no longer be used for (new) mail user accounts, and aliases for these addresses may direct mail only to the box's administrator(s).
* Backups now use duplicity's built-in gpg symmetric AES256 encryption rather than my home-brewed encryption. Old backups will be incorporated inside the first backup after this update but then deleted from disk (i.e. your backups from the previous few days will be backed up).
* There was a race condition between backups and the new nightly status checks.
* The control panel would sometimes lock up with an unnecessary loading indicator.
* You can no longer delete your own account from the control panel.

Setup:

* All Mail-in-a-Box release tags are now signed on github, instructions for verifying the signature are added to the README, and the integrity of some packages downloaded during setup is now verified against a SHA1 hash stored in the tag itself.
* Bugs in first user account creation were fixed.

require TLS on SMTP submission (port 587) to prevent accidental client misconfiguration, although this has no other practical consequences since without TLS clients couldn't authenticate anyway

Even though SMTP (on port 25) is typically opportunistic and a MitM attack can't be prevented, we may as well only offer ciphers that provide some level of security. If a client is so old or misconfigured that it doesn't support newer ciphers, it should hopefully fall back to a non-TLS connection.

Postfix's default was basically anything goes (anonymous and 40-bit ciphers!). Google's MTA's only offer ciphers at 112 bits at greater, and this change approximates that with Postfix's "medium" setting.

Fixes #371

This disallows aNULL and other bad ciphers in the Postfix submission server.

I missed an option in 45e93f7d recommended by the blog post I was reading.

Fixes #389.

https://discourse.mailinabox.email/t/nsd-service-not-started-at-startup-dns-not-working/449