[exim] problem with sf.net

Hi,

I have a problem with sf.net that I can't really pinpoint. After reading
the verizon thread I set my ident timeout to 10 seconds, but that didn't
change anything. Now I've turned it off ("rfc1413_hosts =") and still
get this. It looks as though sf.net is trying to do ident lookups, but
the tcp connection is totally empty. Is anyone else experiencing this?
More details below.

I'm trying to send a mail to someuser@???, which has mx
externalmx-1.sourceforge.net (well, it is listed second now but my exim
tries sending there).
Their server claims to be exim 4.41, I am have 4.44

Here's a sample:

220 mail.sourceforge.net sc8-sf-mx1.sourceforge.net ESMTP Exim 4.41 Wed, 23 Feb 2005 08:06:21 -0800
EHLO sipsolutions.net
250-sc8-sf-mx1.sourceforge.net Hello sipsolutions.net [66.160.135.76]
250-SIZE 1048576
250-EXPN
250-PIPELINING
250-STARTTLS
250 HELP
MAIL FROM:<johannes@???> SIZE=2826
RCPT TO:<.....@users.sourceforge.net>
DATA
250 OK
451-Could not complete sender verify callout
451-Could not complete sender verify callout for <johannes@???>.
451-The mail server(s) for the domain may be temporarily unreachable, or
451-they may be permanently unreachable from this server. In the latter case,
451-you need to change the address or create an MX record for its domain
451-if it is supposed to be generally accessible from the Internet.
451 Talk to your mail administrator for details.
503 valid RCPT command must precede DATA
QUIT
221 sc8-sf-mx1.sourceforge.net closing connection

At the same time, sourceforges server connects to me, but sends nothing
but "QUIT" to which my exim reacts with telling it about synchronisation.

johannes