strange pop protocol?

[Stefan Palme]

I've just took a look on the exact POP-3 spec. There seems to
be another problem:

> ----------------------------------------------------
> +OK <98640940.1241005202 at imap.example.com> imap.example.com Cyrus POP3 v2.3.13-Gentoo server ready
> USER username
> +OK Name is a valid mailbox
> PASS passphrase
> +OK Mailbox locked and ready
> ...
> RETR 2
> DELE 1
> DELE 2
> QUIT
> ----------------------------------------------------

As far as I understood, a POP3 server must ALWAYS send a response
(+OK or -ERR). But in my case the server does not response at all.

Any hints why/how this can happen? I see this behaviour very
often on the wire. Maybe it is worth mentioning that the client
in this case is MS Exchange.

Thanks and regards
-stefan-