I do NOT want my email synchronized. Do I use POP3 or IMAP?

[Mark F]

I do NOT want my email synchronized. Do I use POP3 or IMAP?


I though that POP3 doesn't synchronize between systems and
IMAP does, but POP3 seems to synchronize between the
email server and the phone when using the eMail app
and a POP3 server on the Samsung Galaxy S III.

I had been using POP3 and various email programs
(ISPs' browser interfaces, Outlook Express, Agent, eMail, K-9 Mail,
Thunderbird) with no problems, but then I got a Samsung Galaxy S III
A710 and I found that the "eMail" application on the phone actually
synchronizes with the server when the application "Sync"s.
(My other phones and devices only do downloads when checking a
server, so deleting a message on the server does not delete the
message on any devices. Yes, I have to delete each message on
every interface that I use on every machine that I use, but I
don't have to worry about all my copies of all of my messages
on a server going away because the email service provider
accidentally deleted all of the messages for everybody on all of
their servers.)

I though that POP3 would not delete from the server unless the
email application was configured to delete messages from the server,
and that deleting a message on a server never resulted in an
application that used POP3 having a message that it had downloaded
earlier getting deleted because it was no longer on the server,
and that is how things worked for me using my Droid.

However, when I got a Samsung Galaxy S III and setup my
email with the eMail program that came with the phone, I found that
if I deleted a message on the server it would be deleted from
eMail on the phone the next time eMail "Sync"ed. (K-9 Mail
works the way that I expected, which is that I have to explicitly
delete messages on the phone using the K-9 Mail application, even
though the message K-9 Mail checked for new messages on the
server after message had been deleted on the server.)

I am using the pop3.verizon.net server, but Samsung support
says that the problem happens with other servers. (Samsung says
that the eMail application on the Galaxy S III is provided by Google,
but I haven't been able to find out anything from Google. Note that
the Droid people at Motorola say that the eMail application
on the Droid is also provided by Google and I haven't been able to
get the eMail program on the Droid to work correctly [due to a
different] problem, which I why I knew about the K-9 Mail program
in the first place.])

[Sam]

Mark F writes:

> I though that POP3 would not delete from the server unless the
> email application was configured to delete messages from the server,

Only if "configured to delete messages" means "do it every time".
Originally, POP3 was used only as a mailbox where a POP3 client downloads
all messages from, then immediately deletes them.

Each time a POP3 client would connect to a POP3 mailbox, it would
automatically download all messages locally, and delete them. All mail is
kept on the client's side.

> and that deleting a message on a server never resulted in an
> application that used POP3 having a message that it had downloaded
> earlier getting deleted because it was no longer on the server,
> and that is how things worked for me using my Droid.

Nobody puts a gun to the head of whoever writes a POP3 client and tells them
this is how they must do it. If someone feels like they want to keep
messages in a POP3 maildrop, ala IMAP, and synchronize against it, POP3 has
the facilities that enable this kind of an approach too.

> I am using the pop3.verizon.net server, but Samsung support
> says that the problem happens with other servers. (Samsung says

There is no "problem". If this is how its written to work, then this is how
it works. That's it. Samsung support is, unsurprisingly, clueless.

[Joel Reicher]

Mark F <mark...@gmail.com> writes:

> I do NOT want my email synchronized. Do I use POP3 or IMAP?

You can use either.

The idea of "synchronizing" means you have independent copies of your
mail stored in more than one place.

Arguably, neither POP3 nor IMAP are intended to support multiple
copies, so you won't get synchornizing with either of them in normal
operation.

IMAP is intended for the one and only copy of the email to be on the
server (although it may be cached on a local device in various ways).

POP3 is intended for the one and only copy of the email to be on the
client, once it has been "picked up" from the server.

Both protocols may be "hacked" to achieve multiple stores, although
POP3 is most often used for this by simply skipping the "delete" part
of the typical "download-and-delete" operation.

So if you want email without synchronizing, decide where you want it
stored (if server, use IMAP; if client, use POP3), and then use the
protocol the way it's intended to be used.

> I though that POP3 would not delete from the server unless the
> email application was configured to delete messages from the server,
> and that deleting a message on a server never resulted in an
> application that used POP3 having a message that it had downloaded
> earlier getting deleted because it was no longer on the server,
> and that is how things worked for me using my Droid.

POP3 provides a download command and a delete command; that's pretty
much it.

How those commands are used is up to your client.

> However, when I got a Samsung Galaxy S III and setup my
> email with the eMail program that came with the phone, I found that
> if I deleted a message on the server it would be deleted from
> eMail on the phone the next time eMail "Sync"ed. (K-9 Mail
> works the way that I expected, which is that I have to explicitly
> delete messages on the phone using the K-9 Mail application, even
> though the message K-9 Mail checked for new messages on the
> server after message had been deleted on the server.)

It sounds like your phone's client is using POP3 to "hack" a
synchronizing behaviour. If it's not what you want, change the
software; the protocol is not the problem.

Cheers,

- Joel