spamassassin not checking all incoming mails

[dipeshmehta]

Hello,

I have setup ISPConfig alongwith bundled spamassassin on Ubuntu 8.04 server.

I doubt that all incoming mails are not being checked by spamassassin. Following is a copy of header of received mail -

Return-Path: <wuz_gd@yahoo.cn>
X-Original-To: web2_user1@localhost
Delivered-To: web2_user2@server1.example.com
Received: by server1.example.com (Postfix)
id C8F0D26641; Wed, 10 Dec 2008 10:15:44 +0530 (IST)
Delivered-To: web2_user1@localhost
Received: from server1.example.com (localhost [127.0.0.1])
by server1.example.com (Postfix) with ESMTP id 7B4582662E
for <web2_user1@localhost>; Wed, 10 Dec 2008 10:12:28 +0530 (IST)
Delivered-To: example.com-ispuser@example.com
Received: from pop.example.com [xxx.xxx.xxx.xxx]
by server1.example.com with POP3 (fetchmail-6.3.8)
for <web2_user1@localhost> (single-drop); Wed, 10 Dec 2008 10:12:28 +0530 (IST)
Received: (qmail 32178 invoked from network); 10 Dec 2008 04:42:48 -0000
Received: from unknown (HELO ispmailserver.com) (67.15.238.68)
by ispmailserver.com with SMTP; 10 Dec 2008 04:42:46 -0000
Received: from web92207.mail.cnh.yahoo.com (web92207.mail.cnh.yahoo.com [203.209.250.120])
by ispmailserver.com (Postfix) with SMTP id B014A1670172
for <ispuser@example.com>; Tue, 9 Dec 2008 22:42:27 -0600 (CST)
Received: (qmail 94523 invoked by uid 60001); 10 Dec 2008 04:38:08 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
s=s1024; d=yahoo.cn;
h=X-YMail-OSG:Received:X-Mailerate:From:Subject:To:MIME-Version:Content-Type:Message-ID;
b=xfLAz5thcCUkkqlA6orCVn0nJFU5k6cVmG0xVTkNUG5eShiS USmtdJaDEWsXAkG/qU99gQ9E6Zv0aPqNtbr9UdKikUO0YXjNwiL1WmCka4F54vydpO knzk0jJWULSU4YoELMGIEhEAgUfCBKVY+UaZ+xmBX2DYps7s4C 5EEbQvs=;
X-YMail-OSG: ANghIzUVM1nmq.k7ttIWvDz5Mmd0PwJ1IHrcyKeXF67bRbu_KY L6iJqQLVpiegvALr_pY_G7_zrYG7x5EtC9iTPtsGCfzx2vcKiN UOA0fKwuZtkv0geLEKffB8GNn1JG1OP8pl3QjcVoMPArtgVdAY bWnNXY87_Y2_hNVBsYJA--
Received: from [116.21.41.160] by web92207.mail.cnh.yahoo.com via HTTP; Wed, 10 Dec 2008 12:38:07 CST
X-Mailer: YahooMailWebService/0.7.260.1
Date: Wed, 10 Dec 2008 12:38:06 +0800 (CST)
From: Wuz <wuz_gd@yahoo.cn>
Subject: Merry Christmas greeting from Ms. Ivy
To: wuz_gd@yahoo.cn
MIME-Version: 1.0
X-Security: message sanitized on server1.example.com
See http://www.impsec.org/email-tools/sanitizer-intro.html
for details. $Revision: 1.151 $Date: 2006-01-20 07:29:24-08
X-Security: The postmaster has not enabled quarantine of poisoned messages.
Content-Type: multipart/mixed; boundary="0-691368630-1228883887=:93190"
Message-ID: <756245.93190.qm@web92207.mail.cnh.yahoo.com>
X-Virus-Status: No
X-Virus-Checker-Version: clamassassin 1.2.4 with clamscan / ClamAV 0.94/8740/Wed Dec 10 07:40:20 2008

--0-691368630-1228883887=:93190
Content-Type: multipart/alternative; boundary="0-886007949-1228883887=:93190"

--0-886007949-1228883887=:93190
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

Dear Sir or Madam,

Here I dont see -

X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on server1.example.com
X-Spam-Level:
X-Spam-Status: Yes/No, score=x.x required=5.0 tests=HTML_IMAGE_RATIO_02,
HTML_MESSAGE,RDNS_NONE autolearn=no version=3.2.5

which is there in almost all other mails.

Please guide...

Dipesh