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

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