为什么我的服务器速度会变慢？

caffeine

服务器 co8.8800.org，现在运行的服务有httpd mysqld vsftpd。
原来速度一切正常，自从前半个月机箱电源风扇坏掉以后，时不时的就连不上(通过ssh来连接)而且自己用windows开网页也非常慢，只有reboot linux服务器后速度才恢复正常，不知我是不是受到攻击了？现贴出/var/log/message　的近期日志消息，麻烦高手帮我看看。小弟不胜感激。

Nov 29 21:42:54 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 21:43:50 niank-server pam_userdb[6139]: user 'test' granted acces
Nov 29 21:43:50 niank-server pam_userdb[6139]: user 'test' granted acces
Nov 29 21:44:11 niank-server pam_userdb[6148]: user 'test' granted acces
Nov 29 21:44:11 niank-server pam_userdb[6148]: user 'test' granted acces
Nov 29 21:44:14 niank-server pam_userdb[6150]: user 'test' granted acces
Nov 29 21:44:14 niank-server pam_userdb[6150]: user 'test' granted acces
Nov 29 21:45:36 niank-server kernel: Bad packet from ppp0:IN=ppp0 OUT= MAC= SRC=211.9.167.235 DST=60.163.5.88 LEN=48 TOS=0x00 PREC=0x00 TTL=108 ID=53963 DF PROTO=TCP SPT=3690 DPT=11789 WINDOW=65535 RES=0x00 SYN URGP=0
Nov 29 21:49:09 niank-server pam_userdb[6232]: user 'test' granted acces
Nov 29 21:49:09 niank-server pam_userdb[6232]: user 'test' granted acces
Nov 29 21:50:34 niank-server pam_userdb[6265]: user 'test' granted acces
Nov 29 21:50:34 niank-server pam_userdb[6265]: user 'test' granted acces
Nov 29 21:50:57 niank-server pam_userdb[6282]: user 'test' granted acces
Nov 29 21:50:57 niank-server pam_userdb[6282]: user 'test' granted acces
Nov 29 21:53:02 niank-server pam_userdb[6321]: user 'test' granted acces
Nov 29 21:53:02 niank-server pam_userdb[6321]: user 'test' granted acces
Nov 29 21:53:59 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 21:53:59 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 21:53:59 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 21:54:05 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 21:54:05 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 21:54:05 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 21:54:13 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 21:54:13 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 21:54:13 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 21:56:44 niank-server pam_userdb[6368]: user 'test' granted acces
Nov 29 21:56:44 niank-server pam_userdb[6368]: user 'test' granted acces
Nov 29 21:58:02 niank-server sshd(pam_unix)[6379]: session opened for user root by (uid=0)
Nov 29 21:58:03 niank-server pam_userdb[6387]: user 'test' granted acces
Nov 29 21:58:03 niank-server pam_userdb[6387]: user 'test' granted acces
Nov 29 21:59:13 niank-server vsftpd: vsftpd shutdown succeeded
Nov 29 21:59:28 niank-server sshd(pam_unix)[6379]: session closed for user root
Nov 29 21:59:43 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 21:59:43 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 21:59:43 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 21:59:46 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 21:59:46 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 21:59:46 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 21:59:51 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 21:59:51 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 21:59:51 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 22:00:25 niank-server sshd(pam_unix)[6475]: session opened for user root by (uid=0)
Nov 29 22:02:28 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 22:02:28 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 22:02:28 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 22:02:33 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 22:02:33 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 22:02:33 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0
Nov 29 22:02:40 niank-server dhcpd: if IN A user.cx.com domain doesn't exist add 21600 IN A user.cx.com 192.168.0.3 add 21600 IN TXT user.cx.com "31c9a1001a32fe983d8d2893e6bccfb507": timed out.
Nov 29 22:02:40 niank-server dhcpd: DHCPREQUEST for 192.168.0.3 from 00:11:09:44:63:7c (user) via eth0
Nov 29 22:02:40 niank-server dhcpd: DHCPACK on 192.168.0.3 to 00:11:09:44:63:7c (user) via eth0

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seablue

绑定(灌水):p