[Dovecot] Strange POP3 problem...

[Jürgen Herz]

Mike Cisar wrote:

> Essentially the user will have a number of messages in their mailbox (today
> for example 13) the download of mail will go just fine until one particular
> message and then the download will just stop, eventually returning an error
> message.  Trying to receive mail again will retrieve messages 1-9 again and
> fail in the same spot.  If you log in via IMAP and delete the following
> message (ie. the message after the one that was last received) you can then
> POP for mail again and the remaining messages in the mailbox will download.
>
> [...]
> 
> Any thoughts?

Yes, virus scanner and firewalls.
Does the user have such on his computers? I've experienced some cases
where such programs inspect the traffic between MUA and server and hang
if they encounter unexpected line terminators (single LF) or null bytes.

A windump log from the customers computer when receiving such a message
would be very helpful in any case.

Jürgen