[Exim] unexpected disconnection

Hey,

i got today this in my maillog:

Oct 21 06:22:42 nethawk exim[12715]: 2001-10-21 06:22:42
unexpected disconnection while reading SMTP command from
(localhost) [203.229.225.107]

My problem:
localhost isn't 203.229.225.107 !

Someone tried to use my server as a relay ?

I run my own nameserver, /etc/hosts is ok,
where does exim get the information, that localhost is
203.229.225.107 ?

I am confused.

Greetings Torsten