clear sendmail mail queue

rm -f /var/spool/mqueue/*

php memcache

1. install memcached

wget http://dag.wieers.com/rpm/packages/rpmforge-release/rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm
rpm --install rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm

Or
http://dag.wieers.com/rpm/packages/rpmforge-release/rpmforge-release-0.3.6-1.el5.rf.i386.rpm
rpm --install rpmforge-release-0.3.6-1.el5.rf.i386.rpm

yum install --enablerepo=rpmforge memcached

2. download memcache.php
wget http://livebookmark.net/memcachephp/memcachephp.zip

3. start memcache

service memcached restart
/usr/local/bin/memcached -d -u root -m 512






Reference:
http://www.howtoforge.com/php_memcache_centos5.0
http://www.nioxiao.com/php-memcached
http://www.ibm.com/developerworks/cn/opensource/os-php-fastapps3/index.html

smtp receive mail error

ERROR:
(reason: 553 5.3.5 system config error)
config error: mail loops back to me (MX problem?)
554 5.3.5 Local configuration error
Diagnostic-Code: SMTP; 553 5.3.5 system config error

SOLUTION:
If it is Sendmail that you're using, then you should be able to just edit the /etc/mail/local-host-names file and add your domain names that the MTA should recognize as being its self.

REFERENCE:
http://www.webdeveloper.com/forum/showthread.php?t=173882
open webmail