服务器疑似被用来做代理，查不出原因

服务器apache的日志经常有如下信息，我开启了iptable服务后，只放开httpd和ssh端口的访问，手工都无法连接上 mx3.mail2000.com.tw:25 ，
apache日志依然有connect的日志，并且是成功的。apache肯定是没有开启代理服务的，我重装了系统，手工重新编译安装了最新的php和apache，问题依旧
不知道如何解决
[root@gzyxl logs]# /usr/local/apache2/bin/httpd -v
Server version: Apache/2.4.12 (Unix)
Server built:   Jan 30 2015 20:14:51
[root@gzyxl logs]# /usr/local/php/bin/php -v
PHP 5.6.5 (cli) (built: Jan 30 2015 21:55:27)
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2014 Zend Technologies
[root@gzyxl logs]# lsb_release -a
LSB Version:    :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch
Distributor ID: CentOS
Description:    CentOS release 6.6 (Final)
Release:        6.6
Codename:       Final
编译方式
./configure --prefix=/usr/local/apache2 --enable-mods-shared=all --enable-deflate --enable-speling  --enable-cache --enable-file-cache --enable-disk-cache --enable-mem-cache --enable-so --enable-expires=shared --enable-rewrite=shared --enable-static-support --sysconfdir=/etc/httpd  --with-z=/usr/local/zlib  --with-apr=/usr/local/apr-httpd  --with-apr-util=/usr/local/apr-util-httpd --with-pcre=/usr/local/pcre/ --disable-userdir

./configure  --prefix=/usr/local/php  --with-config-file-path=/usr/local/php/etc --with-apxs2=/usr/local/apache2/bin/apxs --with-mysql=/usr/local/mysql --with-mysqli=/usr/local/mysql/bin/mysql_config --with-libxml-dir=/usr/local/libxml2 --with-png-dir=/usr/local/libpng --with-jpeg-dir=/usr/local/jpeg --with-freetype-dir=/usr/local/freetype --with-gd=/usr/local/gd --with-zlib-dir=/usr/local/zlib --with-mcrypt=/usr/local/libmcrypt --with-xpm-dir=/usr/lib64 --enable-soap --enable-mbstring=all --enable-sockets

发不了网址，只能把日志截图了