error when i change the sysctl env

[=?GB2312?B?1dTD+g==?=]

 freebsd6.0+ipfilter ，
    i use the ipfilter like a firewall proxy my lan connect to the internet
, on my old computer , i use freebsd5.4 and  write the follow lan to the
file sysctl.conf

net.inet.ipf.fr_tcpclosewait=120"
net.inet.ipf.fr_tcplastack=120
net.inet.ipf.fr_tcptimeout=240
net.inet.ipf.fr_tcpclosed=60
net.inet.ipf.fr_tcphalfclosed=300
net.inet.ipf.fr_udptimeout=90
net.inet.ipf.fr_icmptimeout=35

and work fine ,but in the machine of freebsd6.0 ,when boot up ,the system
tall me the device is busy ,and the sysctl env is not alive .i think write
it to the file /boot/loader.conf will be ok  ,but it is not work yet  ,i
dont know what can use that sysctl env  ???
thanks ...

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NAME ：webnamechina
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