DDOS problem from Bangkok, Thailand

[kamolpat at dmaccess.net]

Dear Security team,

I'm Kamolpat Pornatiwiwat, Sys admin of DMaccess Co., Ltd. I'm got the
 problem, My FreeBSD 6.0 got Dos attacked. What should I do? At the
 present, I decide to stop apache and leave only mail feature on
 functioning. Any guide/recommend/solution will be appreciated.

More detail about my server:
======================
FreeBSD 6.0 
apache-1.3.34_4 
php5-5.1.2_1 
MySQL 5.0.20


php.ini
======
;;;;;;;;;;;;;;;;;;;
; Resource Limits ;
;;;;;;;;;;;;;;;;;;;

max_execution_time = 30     ; Maximum execution time of each script, in seconds
max_input_time = 60     ; Maximum amount of time each script may spend parsing r
memory_limit = 32M   (at the beginning it is 8M, I change to 32MB since the cause of httpd-error.log, however, it still the error as the following showed on httpd-error.log


FILE:/var/log/httpd-error.log
=====================
Allowed memory size of 33554432 bytes exhausted ....  happend like this all over  the log

Thanks in Advanced,
Kamolpat Pornatiwiwat, 
Sys admin 
DMaccess Co., Ltd.