My FreeBSD Box's WEB serve sleeps?

[heccj]

My FreeBSD 5.3 Box have Apache MySQL and pureftp serve,and i start them
by adding
*****_enable="YES" in the /etc/rc.conf.
I meet an odd problem:if the clients visit http serve via internet at
the first time will get an erro:can't visit the server,but after a
while,it works very well,and then work very well.Espacially the first
client of one new day often meets this problem.

thanks!