由于搭建的EMOS邮件系统，采用了邮件网关，postfix收发邮件网关都会进行防病毒和反垃圾邮件处理。因此，EMOS自带的防病毒和反垃圾邮件功能就需要停止，顺便提高postfix收发邮件的性能。

 1、修改main.cf配置文件，红色部分为需要注释的部分 

# smtpd related config

smtpd_recipient_restrictions =

       permit_mynetworks,

       permit_sasl_authenticated,

       reject_non_fqdn_hostname,

       reject_non_fqdn_sender,

       reject_non_fqdn_recipient,

       reject_unauth_destination,

       reject_unauth_pipelining,

       reject_invalid_hostname#

#check_policy_service inet:127.0.0.1:10030

#header_checks = regexp:/etc/postfix/dspam_header_checks

# Content-Filter

#content_filter = smtp-amavis:[127.0.0.1]:10024

#receive_override_options = no_address_mappings

       2、修改master.cf配置文件，红色部分为需要注释的部分

#

# DSPAM training settings

#

#retrain unix    –       n       n       –       –       pipe

# flags=Rhq user=dspam argv=/usr/bin/dspam –client –mode=teft –class=$nexthop #–source=corpus –user extmail –deliver=spam,innocent

#spamtrap unix   –       n       n       –       –       pipe

# flags=Rhq user=dspam argv=/usr/bin/dspam –client –mode=teft –class=spam #–source=inoculation –user extmail

#smtp-amavis unix    –    –    n    –    3    smtp

#    -o smtp_data_done_timeout=1200

#    -o smtp_send_xforward_command=yes

#    -o disable_dns_lookups=yes

#    -o max_use=10

然后停掉相关服务，节约系统资源：

service amavisd stop
service clamd stop
service dspam-webd stop
service dspamd stop
service spamassassin stop

chkconfig amavisd off
chkconfig clamd off
chkconfig dspam-webd off
chkconfig dspamd off
chkconfig spamassassin off