Re: [Fetchmail-users] Fetchmail suddenly downloading the same messages over and over

[Rick H. <ric...@ya...>]

Hello again Matthias,
Setting 'uidl' in fetchmailrc was the magic solution thank you!!Fetchmail is now recognising 'seen' messages and not continually downloading all messages.
I've also set 'uidl' globally for the other POP3 mail providers I fetch from as these were complaining with:Dec 15 21:33:39 control fetchmail[23655]: POP3> LAST
Dec 15 21:33:39 control fetchmail[23655]: POP3< -ERR Unknown command: LAST
Dec 15 21:33:39 control fetchmail[23655]: Unknown command: LAST
Dec 15 21:33:39 control fetchmail[23655]: POP3> UIDL
Dec 15 21:33:39 control fetchmail[23655]: POP3< +OK

My thought is that some change at Yahoo's end has caused LAST to stop working as the only recent change I'd made on my side was that fetchmail-6.3.26 was installed in July.
Something else that perhaps confirms some changes by Yahoo in recent days is a new security settings popup that shows when logging into their webmail interface that states:"Some older email applications deploy an older security protocol to sign into your account. Going forward, to further improve the security of your Yahoo Mail experience, Yahoo may block sign in attempts from these older security protocols. We may block email applications that use a no longer recommended sign in method from accessing Yahoo accounts."

Not to mention the mad scramble with changes being made behind the scenes at Yahoo after their latest security breach.
Obviously they'd not blocked fetchmail but perhaps the changes they have made have had the affect of breaking the way fetchmail communicates with their servers using LAST.
Your suspicion of the .fetchids file entries being filled by other providers was also spot on.Once 'uidl' was set and fetchmail had re-fetched all the 'seen' messages one final time from Yahoo, the number of entries in .fetchids increased by roughly the same amount of Yahoo 'seen' messages.
Thanks again for providing a solution, let me know if you need me to do anything else to help debug.

Cheers,Rick 

    On Saturday, 17 December 2016, 14:19, Matthias Andree <mat...@gm...> wrote:
 

 Greetings,

Rick has sent me verbose traces off-list, and they show that fetchmail
6.3.26 talks "LAST" with the server, but not UIDL, so I presume any
.fetchids are from other accounts.

Rick, I propose, as a band-aid, to try the --uidl option on the command
line, or uidl in the rcfile, either one should be sufficient to try and
enforce the use of UIDL instead of LAST.

I haven't yet followed the fetchmail code paths because "LAST" is hardly
used and I don't recommend it, and I need some quality time to debug
that - and note that LAST has also been pulled from the standard¹
(because it gets confused and can cause clients to skip mail when a
second other client accesses the same mailbox), but chances are that
somewhen in the late 6.2 or in the 6.3 phase the LAST code has
regressed. I will remove it from one of the future fetchmail versions
anyhow, and to be honest I'll only do a 6.3.26.1 with that one fix if
it's low-hanging fruit or else add a FAQ item.

¹ it used to be part of RFC1725 of 1994, but was removed in RFC1939 in
May 1996.

Cheers,
Matthias