I have a homegrown POP3 bridge server.
It implements the basic commands plus CAPA with TOP and UIDL.
Thunderbird is requesting:
USER
PASS
STAT
LIST
UIDL
NO… (और पढ़ें)
I have a homegrown POP3 bridge server.
It implements the basic commands plus CAPA with TOP and UIDL.
Thunderbird is requesting:
- USER
- PASS
- STAT
- LIST
- UIDL
- NOOP
- RETR
Notes:
- The response of STAT correctly tells how many e-mails exist but the size announced is dummy and doesn't match the real sum of the size of the e-mails (nor the sum of the sizes output by LIST).
- The response of LIST correctly tells how many e-mails exist the size of each one is dummy but different numbers. Each element of a list corresponding to the same e-mail always has the same published size.
- If the oldest e-mail is deleted, LIST will shift all values
- In the response of UIDL, the uid is unique. Deleting an e-mail won't cause a reuse of the uid.
Thunderbird settings set:
- "Fetch headers only" unticked.
- "Leave messages on server" ticked and unticked the part of "For most" and "Until I delete them".
- Everything else is set to default settings.
Thunderbird user behavior:
- Thunderbird is accessing and downloading e-mails.
- E-mails listed, are listed with just default variable values (see email_appearance.png)
- If I open properties and press repair folder, all messages appear normal as if it's fixed. But it's not because all new e-mail continues having the same issue.
- E-mails downloaded open correctly, including attachments, and display all metadata correctly. I.e While in the list the date is the default, in the GUI of the e-mail header, it appears correctly. Same for subject and all other headers that thunderbird displays.
- Sometimes, Thunderbird decides to download all e-mail a second time.
Thunderbird unexpected behavior with server:
- Sometimes, there is a new e-mail and another e-mails is deleted in the server. Thunderbird requests STAT and then assumes there is no new e-mails even though the size reported changes.
- Sometimes, there is a new e-mail. Thunderbird uses command STAT which responds differently from the STAT in the previous session (E.g. 1 more e-mail and higher size) but thunderbird displays in the interface as if there's no new e-mail.
- Sometimes, thunderbird executes STAT, then LIST, then decides to download all e-mail, even without executing UIDL command to confirm the e-mail uids. I don't know when that happens.
Examples:
These responses lead to a full re-download of all listed e-mail.:
STAT:
+OK 14 85539
LIST:
+OK 14 messages
1 1910
2 2692
3 8118
4 1101
5 3910
6 8916
7 6456
8 6500
9 6518
10 6602
11 7595
12 9363
13 9369
14 6489
.
UIDL:
+OK 14 messages
1 2311910
2 2312692
3 2328118
4 2323011
5 2313910
6 2338916
7 2346456
8 2346500
9 2346518
10 2346602
11 2347595
12 2349363
13 2349369
14 2356489
.
-> Then it downloads all e-mail.
Next connection,
STAT:
+OK 15 92559
-> Thunderbird doesn't do anything and doesn't download the new e-mail.
5 connections later, I delete a few e-mails in the server
STAT:
+OK 12 72939
LIST:
+OK 12 messages
1 1910
2 2692
3 8118
4 1101
5 3910
6 8916
7 6456
8 7595
9 9363
10 6489
11 9369
12 7020
.
UIDL:
+OK 12 messages
1 2311910
2 2312692
3 2328118
4 2323011
5 2313910
6 2338916
7 2346456
8 2347595
9 2349363
10 2356489
11 2349369
12 2357020
.
-> Thunderbird downloads (RETR) all e-mails.
Why is thunderbird downloading all e-mails?
Issues in analysis:
- Downloaded e-mails appear listed without their subject and date appears as default although all of that data is in the e-mail. Repairing .msf file makes it appear correctly.
- Thunderbird is downloading all e-mails every time it contacts the server and it considers there's an update.
Thunderbird version: 128.7.1esr
I don't have any antivirus and I'm using an ubuntu 24.04 variant.