how to prevent this?

hi,

we use exim3 aon our site for mailtransfer.
yesterday we had a problem that we received a lot of "Mail delivery failed:
returning message to sender"

someone tryed a lot of "names" for our domain and each time we got this in
our mainlog of exim:

2005-06-04 07:16:19 1DeR16-0008Ng-00 <= support@widor.de
H=p54b118ac.dip0.t-ipconnect.de (widor.de) [84.177.24.172] P=esmtp S=65053
2005-06-04 07:16:19 1DeR16-0008Ng-00 ** anna@widor.de: unknown local-part
"anna" in domain "widor.de"
2005-06-04 07:16:19 1DeR19-0008Nk-00 <= <> R=1DeR16-0008Ng-00 U=mail P=local
S=65922
2005-06-04 07:16:19 1DeR16-0008Ng-00 Error message sent to support@widor.de
2005-06-04 07:16:19 1DeR16-0008Ng-00 Completed
2005-06-04 07:16:19 1DeR19-0008Nk-00 ** support@widor.de: unknown local-part
"support" in domain "widor.de"
2005-06-04 07:16:19 1DeR19-0008Nk-00 support@widor.de: error ignored
2005-06-04 07:16:19 1DeR19-0008Nk-00 Completed
2005-06-04 07:18:21 1DeR35-0008No-00 <= mail@widor.de
H=p54b118ac.dip0.t-ipconnect.de (widor.de) [84.177.24.172] P=esmtp S=65035
2005-06-04 07:18:21 1DeR35-0008No-00 ** sam@widor.de: unknown local-part
"sam" in domain "widor.de"
2005-06-04 07:18:22 1DeR38-0008Ns-00 <= <> R=1DeR35-0008No-00 U=mail P=local
S=65892
2005-06-04 07:18:22 1DeR35-0008No-00 Error message sent to mail@widor.de
2005-06-04 07:18:22 1DeR35-0008No-00 Completed
2005-06-04 07:18:22 1DeR38-0008Ns-00 ** mail@widor.de: unknown local-part
"mail" in domain "widor.de"
2005-06-04 07:18:22 1DeR38-0008Ns-00 mail@widor.de: error ignored
2005-06-04 07:18:22 1DeR38-0008Ns-00 Completed
2005-06-04 07:18:53 1DeR3a-0008Nw-00 <= webmaster@widor.de
H=p54b118ac.dip0.t-ipconnect.de (widor.de) [84.177.24.172] P=esmtp S=65109
2005-06-04 07:18:53 1DeR3a-0008Nw-00 ** brenda@widor.de: unknown local-part
"brenda" in domain "widor.de"
2005-06-04 07:18:53 1DeR3d-0008O0-00 <= <> R=1DeR3a-0008Nw-00 U=mail P=local
S=65990
2005-06-04 07:18:53 1DeR3a-0008Nw-00 Error message sent to
webmaster@widor.de
2005-06-04 07:18:53 1DeR3a-0008Nw-00 Completed
2005-06-04 07:18:53 1DeR3d-0008O0-00 => vw <webmaster@widor.de> D=localuser
T=local_delivery
2005-06-04 07:18:53 1DeR3d-0008O0-00 Completed

so it seems for me, that someone claims to be the smtp for our domain (but
that is not our host; we have another ip):
2005-06-04 07:16:19 1DeR16-0008Ng-00 <= support@widor.de
H=p54b118ac.dip0.t-ipconnect.de (widor.de) [84.177.24.172] P=esmtp S=65053

the there is something like a list to mail errormessages to - in this case
this is support@, mail@, webmaster@ (and webmaster@ hits a real address).

so, i do not real understand why there is an "** brenda@" after webmaster@
in the log.

so the question is, is there something misconfigured on our server?

--
Volker Widor - Krausstr. 13 - D-24118 Kiel
Fon.: +49 431 2212130 Mobil: +49 179 7593660
http://volker.widor.de