another strange pop protocol

[Stefan Palme]

Hello,

We are running Cyrus IMAP Server 2.3.13 to store user mails. One of
our customers uses MS Exchange to fetch the mails from our server to
their MS Exchange system (from where the mails are distributed to the
correct users in the customers intranet).

Because customer complaints about times where MS exchange seems to
not get any mails from our server, I have enabled telemetry logs for
this customer. And I see the following strange stuff:

--------------------------------------------------------------
>1242398161>+OK Mailbox locked and ready
<1242398161<UIDL
>1242398161>+OK unique-id listing follows
1 1157352258.222464
2 1157352258.222465
3 1157352258.222466
... (about 50 entries here)
.
<1242398161<LIST
>1242398161>+OK scan listing follows
1 7863531
2 8217
3 20990
.... (again about 50 entries)
.
<1242398162<RETR 1
>1242398162>+OK Message follows
Return-Path: <xxx at example.com>
Received: ....
// here I see the full email text. It is a multipart message with
// an embedded image. The telemetry log ends with the following lines:
IUWtBzN7/RTufRknUldIObFYpX3ePOWjJ+QOZr64SxMqTcMfjPnlUZAITORwBgeQCzFXlm/icEme
MxGlMsDlwyDm56B2y0ApxEU3Mp6PphmQp9MdeHyF2/hQdKGR5TXksATQSImK+gZHlp1eqV2pWJT1
oE0P5uNEzvAg1fHGqxKvMacC84VSdqd08Ub9<1242399992<RETR 2
---------------------------------------------------------------------------

It looks like the receiving of the email did not finished normally (I
think, there should be at least one LF in the end), and the client 
sends the next "RETR" command. But here the telemetry logs ends. How can
this happen? 

Maybe it is interesting to see, that the timestamp of the second RETR
command (@1242399992) is almost exactly 30 minutes after the timestamp
of the first RETR command (@1242398162). So it seems to take more than
half an hour to fetch this email. Maybe this is a timeout problem - but
is this a problem of the client or the server?


Furthermore, in the middle of the base64 encoded image I see the
following:

4FDWzMp4Ltf3bFgyyNLKiWMQUcgyFtVgO73YWiS+EWnv9Y1NlLrfRa0wZysZIW3+kqZhhpqPjujl
N+wKHNftm6KbJtN6GcRG0bCqbbZXKni++L/cPXs9XfkmwJf314gu1Em50+3G66UMeBBx6T6uvBtO
Nxzol2Kk4wGdy/pho1uqO8y2ATNpkVARTT7plfFjxr9z5AQc/xpqIoWZhTmdWtVlUPzfk/PvrI>1242399991>9G
YHuVwgObMjJc1PR+xp+PJhweX5wWU9rhIHmDDWEt6Y+m7K/qHS6DOtMPj0yAcaD5BFamBnRl6Jkv
XnH69+w8l+y8YPACzuIslMR2uNpCYcN8fDKPem1T+FshPLCainNwYyko+U8B2LdyF6UfL8DwZZpy


(See the end of the line in the middle). It looks like the cyrus server
mixes some strange output (">1242399991>") into the telemetry logs (and
maybe this also makes the connection somehow "broken"?).


Anybody knows what's the problem here and how to solve it?

Thanks and regards
-stefan-