how to configure syslog-ng to push log to log server

[Gentoo]

Hi all
I want to configure syslog-ng on one of my cfengine client to collect
all cfengine log from all boxes.

now I almost succeed, but have a problem.
entry in syslog-ng will duplicate! would someone take a look at it, please?
thanks for your time.

Jul  3 05:22:29 sles9 cfservd[11975]:  Unable to lookup hostname
(tux.**.**.com) or cfengine service: Name or service not known
Jul  3 05:22:29 geometry cfservd[11975]:  Unable to lookup hostname
(tux.*.*.com) or cfengine service: Name or service not known

and here is my syslog-ng.conf about cfengine --on syslog-ng loghost
destination cfengine { file("/var/log/cfengine.log"); };
filter f_cfengine { program("cfservd"); };
filter f_messages   { not facility( mail, cron) and not filter (f_cfengine); };
log { source(src); filter(f_cfengine); destination(cfengine); };


syslog-ng.conf about cfengine --on cfengine server

filter f_cfengine { program("cfservd"); };
filter f_messages   { not facility(news, mail, cron) and not filter
(f_cfengine); };

destination d_loghost { udp("server IP"); };
log { source(src); filter(f_cfengine); destination(d_loghost); };

-- 
Life is hard