For some years, I've been running my own email server on a virtual
machine somewhere in Canada. This was in response to the previous
commercial email service constantly being blacklisted due to having spam originate from it.

Since my server was supporting only one domain, it was expecting only
user names for authentication, and not full email addresses.

Also, in order to be able to delete email addresses easily should they
start to suffer spam, the names of the mailboxes are never exposed, and
all email addressed made public are aliases.

But I'm getting too old for this, and decided to move everything back to
a commercial service, in the hope that things have improved over the
years. In preparation I made one small change, which was to set a flag
that makes system strip off the domain name part of the names used to authenticate to the server. That is, if the user's client supplies a
domain name when authenticating, it is just completely ignored.

That's it. That's all I changed.

So, why oh why, did I discover the next day that desktop Thunderbird had decided to change the login name from what it was meant to be, to the
alias email address of the user?

And why did Samsung's Android email client do the same?

Fixing Thunderbird was a matter of giving it a stern talking to.

But the Android email client? I did battle with it for several hours,
before conceding that I'd have to delete the account (and hence all the
emails it contained), and start from scratch.

Did my tiny change really cause all this? If so, how? Or was it some
bizarre coincidence?

Sylvia.

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Sun, 20 Sep 2026 18:51:47 +0800, Sylvia Else wrote:

Did my tiny change really cause all this? If so, how? Or was it some
bizarre coincidence?

I would have tried changing it back.

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Sylvia Else <sylvia@email.invalid> writes:

But I'm getting too old for this, and decided to move everything back
to a commercial service, in the hope that things have improved over
the years. In preparation I made one small change, which was to set a
flag that makes system strip off the domain name part of the names
used to authenticate to the server. That is, if the user's client
supplies a domain name when authenticating, it is just completely
ignored.

That's it. That's all I changed.

I would suggest reviewing the diff of the configurations before and
after the change, to verify that the change is what you thought it was.

So, why oh why, did I discover the next day that desktop Thunderbird
had decided to change the login name from what it was meant to be, to
the alias email address of the user?

And why did Samsung's Android email client do the same?

This doesn?t really pass the sniff test. If two popular email clients simultaneously changed how they deal with usernames overnight (which is
pretty unlikely in the first place) then you?d see a tidal wave of
people complaining they couldn?t access their email.

Did my tiny change really cause all this? If so, how? Or was it some
bizarre coincidence?

There?s not really enough detail in the posting to say anything
certain. e.g. what mail server software is involved, what was the
actual change, etc.

--
https://www.greenend.org.uk/rjk/

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Insomnia 24/7 fails to receive a subset of emails which were
definitely sent to it. (These failures might not be a fault of
Insomnia 24/7.)

So I may need to consider using a different emails provider. Please
suggest which emails servers to use or to avoid.

(S. HTTP://Gloucester.Insomnia247.NL/ fuer Kontaktdaten!)

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 21-Sept-26 3:55 pm, Richard Kettlewell wrote:

Sylvia Else <sylvia@email.invalid> writes:

But I'm getting too old for this, and decided to move everything back
to a commercial service, in the hope that things have improved over
the years. In preparation I made one small change, which was to set a
flag that makes system strip off the domain name part of the names
used to authenticate to the server. That is, if the user's client
supplies a domain name when authenticating, it is just completely
ignored.

That's it. That's all I changed.

I would suggest reviewing the diff of the configurations before and
after the change, to verify that the change is what you thought it was.

So, why oh why, did I discover the next day that desktop Thunderbird
had decided to change the login name from what it was meant to be, to
the alias email address of the user?

And why did Samsung's Android email client do the same?

This doesn?t really pass the sniff test. If two popular email clients simultaneously changed how they deal with usernames overnight (which is pretty unlikely in the first place) then you?d see a tidal wave of
people complaining they couldn?t access their email.

Did my tiny change really cause all this? If so, how? Or was it some
bizarre coincidence?

There?s not really enough detail in the posting to say anything
certain. e.g. what mail server software is involved, what was the
actual change, etc.

I wasn't really expecting an explanation.

Apparently, there are things that some email clients will do when well
known email service providers issue scripts to change the way that authentication is achieved. That sounds likely to achieve at least as
much chaos as it prevents.

But I really cannot imagine a scenario where it would make sense to
change the login name to be some email alias.

In any case, my mail server is not on anyone's list of well known
service providers, and I haven't issued any scripts.

I could do some experiments, but I'm not really motivated to do so,
since the whole point is to move away from this private email server,
and the result could be yet more pain for my small number of family users.

Sylvia.






--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Sylvia Else <sylvia@email.invalid> writes:

Apparently, there are things that some email clients will do when well
known email service providers issue scripts to change the way that authentication is achieved. That sounds likely to achieve at least as
much chaos as it prevents.

You are probably thinking of RFC6186 SRV records telling mail clients
where to look for IMAP/SMTP/etc servers based on a user?s email
address. But they?re normally used for initial setup, not every
connection. In principle a mail client could poll them every time it
needed to connect, but Thunderbird at least doesn?t.

At any rate they are quite easy to set up and they work fine, millions
of people use them without any trouble.

--
https://www.greenend.org.uk/rjk/

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

The default email client on Apple MacOS guesses stereotypical values
for initially configuring it with email servers.
(S. HTTP://Gloucester.Insomnia247.NL/ fuer Kontaktdaten!)

--- PyGate Linux v1.5.19
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)