Panic! 10,000 assorted spam emails just tried to download to my account

[#1]

When you create a new email account in Thunderbird you get asked if you want to create a POP or IMAP account. For IMAP the server name needed is imap.plus.net.

[#2]

I set up an IMAP account on TB with imap.plus.net as server but when I connect it wants a password - but my usual login password doesn't work on it. Nor does putting in my username.

[#3]

I've got connected with IMAP and it tries to download over 17,000 messages - so POP3 and IMAP show vast amounts of spam, while webmail (connection direct) shows none.
P.S. The apparent problem with the password was because when I set up the IAMP account TB had automatically inserted my usual name as the username instead of asking me for a name. As soon as I changed it to my PN username I got in OK.
EDIT: I logged into webmail again and it shows 17,395 messages "total", so I am wrong about 17,000 spam via IMAP - I suppose it is showing all the messages I've had on the server from year dot! When I briefly connected via IMAP it downloaded about 500 messages from March 2007, many of them tagged as spam. This would be from when I joined PN and at that time the PN spam filter was possibly still on by default, before I switched it of.

[#4]

Do you have POP configured to leave a copy of the email on the server?

[#5]

Quote from: jelv

Do you have POP configured to leave a copy of the email on the server?

Yes - I do have it set on my usual account. There seems to be no such option on the IMAP account.
From the dates of the stuff being downloaded, both by IMAP and POP3, this is beginning to look like a slightly different problem. Most of the email has old dates from March on (I joined about then). So it looks like rather than there suddenly being a big batch of spam, it is trying to download all my old email from the PN server (including spam of which there is much more than non-spam).
[Sorry for delay replying - I've been sitting here refreshing the forum web page every few minutes and didn't realise it had logged me out!]

[#6]

It's not relevant to imap - the whole idea of which is that emails are kept on the server. But is does explain why you have so many emails showing via imap (and hence webmail). It has no idea which emails have been read by POP and left on the server.
If the emails are dead and should have been deleted you should remove them from the server.
With imap you have the option to download and keep email for offline use. Any changes you make (such as deletions and moving emails between folders) will be reflected on the server the next time you connect.

[#7]

But why is it all suddenly coming down (apparently for a second time) in my usual POP3 account?
I was with my previous ISP for more than 10 years and left messages on the server (following their own guidelines) and never had this problem and never was asked to remove them.

[#8]

I think Thunderbird has lost track of the messages it has already downloaded - had you made any configuration changes in Thunderbird?

[#9]

None at all (until the IMAP after the event). All was well first thing this morning, then connected about 30 minutes later and - thousands! I have not done any OS updates in the last few days either.

[#10]

I've certainly had Thunderbird 'forget' that it's downloaded up to a certain number of mails, (although I mainly use IMAP nowadays as it it designed to operate as you seem to require).
It usually follows on from Thunderbird crashing during a mail receiving process.
My recommendation is to use IMAP in preference of POP3 in your circumstances anyway
B.

[#11]

I've just connected to the POP3 server from a different computer (also using Thunderbird) and that is giving exactly the same problem. Which confirms it is not due to any changes in TB. I cannot see TB on two separate PCs both suddenly having a blip on the same day.
I recently asked to be transferred from an old type of PN account to the newer BBYW. It is in progress - I wonder whether this could have had anything to do with the problem? As far as I know I am still on the old account, but someone might have pressed a button somewhere at PN!

[#12]

Quote from: Barry

My recommendation is to use IMAP in preference of POP3 in your circumstances anyway

Barry, Why should IMAP be better for me than POP3 which has been fine for many years? I think my requirements are pretty much standard.

[#13]

POP3 is designed as a temporary store-and-forward mail system.  Mails are queued in your POP3 mailbox with the intention that they are downloaded onto a local machine to be read.
The 'Leave messages on server' option was a workaround introduced in V3 of the POP (Post Office Protocol) which allowed multiple computers access to the same messages from the same mailbox (although not necessarily simultanously).  The intent of the design was that the last client accessing the mailbox would delete all the read mail.
The 'tagging' of which mails have been read is not handled in the POP3 protocol.  The way that mail clients track this is by using client stored information.  AFAIK, the POP3 server has no standard mechanism for announcing that a message has been 'read'.  Thunderbird merely tracks thie highest UIDL (unique message id) that it has 'downloaded' and assumes that anything previous to this does not need to be re-downloaded.  However, if the content store (on your machine) that records this UIDL is damaged, then Thunderbird has no definitive mechanism to identify which mails have already been downloaded.
IMAP, however, was designed from the ground up as a server-based mailbox.  Messages are designed to be left on the server and accessed from multiple locations.  IMAP also supports server-side flags, including message status (whether read or not).
It is also designed in such a way that it can be accessed from multiple locations simultaneously.  Marking a message as read in one location will (almost) immediately mark it as read in another location.
In addition, IMAP allows you to store your 'sent mail' on the server, making it available to all locations.
Thunderbird will allow you to connect to an IMAP mailbox, and also keep an 'offline' copy on your local machine, so you can refer to your mail when not connected to the internet.
B.

[#14]

Quote from: Bookman

I've just connected to the POP3 server from a different computer (also using Thunderbird) and that is giving exactly the same problem. Which confirms it is not due to any changes in TB. I cannot see TB on two separate PCs both suddenly having a blip on the same day.

That is exactly how it should work. The second PC is not psychic and has no idea what emails have been previously downloaded by the previous PC.
POP with the leave messages on the server option set is a kludge and works fine until it goes wrong - then it is a complete and utter pain!

[#15]

Quote from: jelv

POP with the leave messages on the server option set is a kludge and works fine until it goes wrong - then it is a complete and utter pain!

Jelv, What I was getting at here relates to Barry's comment: "However, if the content store (on your machine) that records this UIDL is damaged, then Thunderbird has no definitive mechanism to identify which mails have already been downloaded." It would be an amazing coincidence if the "UIDL" had been damaged on both machines (which belong to different people) in the same half hour this morning. So I am still at a loss to know why the PN server wants to dump all those old message on me.