[Dovecot] pop3 problem with small messages with no Subject: and no To: headers

[Ken A]

Hello,
Seeing a strange thing with dovecot 1.0 b7 pop3.

If a user gets a particular _very_ short spam message (not sure what 
virus makes these..), with NO Subject and NO To: headers and NO body, 
(example available upon request), the user is unable to download the 
mail. The log entry is:

May 10 10:51:35 mail dovecot: POP3(user): Disconnected top=0/0, 
retr=1/1344, del=0/75, size=16383381

There's no QUIT, so no "Logged out" disconnect reason.
I did a tcpdump to see what was happening. I have not been able to 
duplicate this myself yet, even with an exact copy of the message that 
seems to be causing it, so it could be a client issue, but I've never 
seen this before, and we just switched to Dovecot, so I thought I'd 
check with the list.. ideas?

Message #9 is requested (it's the one in the user's box with missing 
headers). Dovecot begins returning it, but then disconnects, or so it seems.

10:51:35.171916 IP customer.60181 > mailserver.pop3: P 40:48(8) ack 1633 
win 65535
         0x0000:  4500 0030 d326 4000 7106 fc20 4624 16a1  E..0.&@.q...F$..
         0x0010:  ceaa 0f11 eb15 006e 7ee7 2a93 d845 fe0c  .......n~.*..E..
         0x0020:  5018 ffff 3618 0000 5245 5452 2039 0d0a  P...6...RETR.9..
10:51:35.172177 IP mailserver.pop3 > customer.60181: P 1633:2980(1347) 
ack 48 win 5840
         0x0000:  4500 056b ca0b 4000 4006 3101 ceaa 0f11  E..k.. at .@.1.....
         0x0010:  4624 16a1 006e eb15 d845 fe0c 7ee7 2a9b  F$...n...E..~.*.
         0x0020:  5018 16d0 3fde 0000 2b4f 4b20 3133 3237  P...?...+OK.1327
         0x0030:  206f 6374 6574 730d 0a52 6574 7572 6e2d  .octets..Return-
         0x0040:  5061 7468 3a20 3c68 7469 3935 6b67 6576  Path:.<hti95kgev
         0x0050:  4072                                     @r
10:51:35.416549 IP mailserver.pop3 > customer.60181: P 1633:2980(1347) 
ack 48 win 5840
         0x0000:  4500 056b ca0d 4000 4006 30ff ceaa 0f11  E..k.. at .@.0.....
         0x0010:  4624 16a1 006e eb15 d845 fe0c 7ee7 2a9b  F$...n...E..~.*.
         0x0020:  5018 16d0 3fde 0000 2b4f 4b20 3133 3237  P...?...+OK.1327
         0x0030:  206f 6374 6574 730d 0a52 6574 7572 6e2d  .octets..Return-
         0x0040:  5061 7468 3a20 3c68 7469 3935 6b67 6576  Path:.<hti95kgev
         0x0050:  4072                                     @r
10:51:35.470688 IP customer.60181 > mailserver.pop3: F 48:48(0) ack 2980 
win 64188
         0x0000:  4500 0028 d329 4000 7106 fc25 4624 16a1  E..(.)@.q..%F$..
         0x0010:  ceaa 0f11 eb15 006e 7ee7 2a9b d846 034f  .......n~.*..F.O
         0x0020:  5011 fabc 09fa 0000 0000 0000 0000       P.............
10:51:35.470997 IP mailserver.pop3 > customer.60181: F 2980:2980(0) ack 
49 win 5840
         0x0000:  4500 0028 ca0f 4000 4006 3640 ceaa 0f11  E..(.. at .@.6 at ....
         0x0010:  4624 16a1 006e eb15 d846 034f 7ee7 2a9c  F$...n...F.O~.*.
         0x0020:  5011 16d0 ede5 0000                      P.......
10:51:35.515279 IP customer.60181 > mailserver.pop3: . ack 2981 win 64188
         0x0000:  4500 0028 d32e 4000 7106 fc20 4624 16a1  E..(.. at .q...F$..
         0x0010:  ceaa 0f11 eb15 006e 7ee7 2a9c d846 0350  .......n~.*..F.P
         0x0020:  5010 fabc 09f9 0000 0000 0000 0000       P.............

That's all, the connection is closed.

Ken A
Pacific.Net