[root@v01-svn-test-server ~]# service iptables status
Table: filter
Chain INPUT (policy DROP)
num target prot opt source destination
1 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:3306
2 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:22
3 ACCEPT all -- 127.0.0.1 127.0.0.1
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 Chain FORWARD (policy DROP)
num target prot opt source destination Chain OUTPUT (policy DROP)
num target prot opt source destination
1 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp spt:3306
2 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp spt:22 state ESTABLISHED
3 ACCEPT all -- 127.0.0.1 0.0.0.0/0
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp spt:80 state ESTABLISHED
[root@v01-svn-test-server ~]# cat /etc/sysconfig/iptables
# Generated by iptables-save v1.4.7 on Wed Jun 1 22:15:41 2016
*filter
:INPUT DROP [24:3081]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 3306 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -s 127.0.0.1/32 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
COMMIT
# Completed on Wed Jun 1 22:15:41 2016
[root@v01-svn-test-server sysconfig]# ping 192.168.1.17
PING 192.168.1.17 (192.168.1.17) 56(84) bytes of data.
ping: sendmsg: Operation not permitted
[root@v01-svn-test-server sysconfig]# cat iptables
# Generated by iptables-save v1.4.7 on Wed Jun 1 22:15:41 2016
*filter
:INPUT DROP [24:3081]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 3306 -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A OUTPUT -p icmp -j ACCEPT #增加这两行可以ping
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -s 127.0.0.1/32 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
COMMIT
# Completed on Wed Jun 1 22:15:41 2016
[root@v01-svn-test-server sysconfig]# ping -c 2 192.168.1.17
PING 192.168.1.17 (192.168.1.17) 56(84) bytes of data.
64 bytes from 192.168.1.17: icmp_seq=1 ttl=64 time=0.862 ms
64 bytes from 192.168.1.17: icmp_seq=2 ttl=64 time=0.585 ms --- 192.168.1.17 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 0.585/0.723/0.862/0.141 ms
[root@v01-svn-test-server sysconfig]# ping www.baidu.com
ping: unknown host www.baidu.com
[root@v01-svn-test-server sysconfig]# ping -c 2 211.155.89.150
PING 211.155.89.150 (211.155.89.150) 56(84) bytes of data.
64 bytes from 211.155.89.150: icmp_seq=1 ttl=52 time=2.78 ms
64 bytes from 211.155.89.150: icmp_seq=2 ttl=52 time=2.58 ms --- 211.155.89.150 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1004ms
rtt min/avg/max/mdev = 2.581/2.683/2.786/0.114 ms
[root@v01-svn-test-server sysconfig]# ping -c 2 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=41 time=60.1 ms --- 8.8.8.8 ping statistics ---
2 packets transmitted, 1 received, 50% packet loss, time 2001ms
rtt min/avg/max/mdev = 60.178/60.178/60.178/0.000 ms
[root@v01-svn-test-server sysconfig]# ping -c 2 8.8.4.4
PING 8.8.4.4 (8.8.4.4) 56(84) bytes of data.
64 bytes from 8.8.4.4: icmp_seq=1 ttl=48 time=51.4 ms
64 bytes from 8.8.4.4: icmp_seq=2 ttl=48 time=55.5 ms --- 8.8.4.4 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1057ms
rtt min/avg/max/mdev = 51.484/53.517/55.551/2.046 ms
#8.8.8.8 和 8.8.4.4 是Google提供的免费DNS服务器的IP地址
[root@v01-svn-test-server sysconfig]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 52:54:00:38:04:CA
inet addr:192.168.1.35 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::5054:ff:fe38:4ca/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:14664740 errors:0 dropped:12405 overruns:0 frame:0
TX packets:24212 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1575721510 (1.4 GiB) TX bytes:3561803 (3.3 MiB)
Interrupt:11 Base address:0x2000 [root@v01-svn-test-server sysconfig]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 1002 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
DNS 端口53的设置：
[root@v01-svn-test-server sysconfig]# grep domain /etc/services
domain 53/tcp # name-domain server
domain 53/udp
domaintime 9909/tcp # domaintime
domaintime 9909/udp # domaintime
[root@v01-svn-test-server sysconfig]# cat /etc/sysconfig/iptables
# Generated by iptables-save v1.4.7 on Wed Jun 1 22:15:41 2016
*filter
:INPUT DROP [24:3081]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 3306 -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A OUTPUT -p icmp -j ACCEPT #增加这两行可以ping
-A INPUT -p udp --sport 53 -j ACCEPT #DNS端口53设置
-A OUTPUT -p udp --dport 53 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -s 127.0.0.1/32 -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
COMMIT
# Completed on Wed Jun 1 22:15:41 2016
注意：上面的注释去掉，不然报错
[root@v01-svn-test-server sysconfig]# ping -c 2 www.baidu.com
PING www.a.shifen.com (61.135.169.121) 56(84) bytes of data.
64 bytes from 61.135.169.121: icmp_seq=1 ttl=54 time=2.19 ms
64 bytes from 61.135.169.121: icmp_seq=2 ttl=54 time=1.88 ms --- www.a.shifen.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1003ms
rtt min/avg/max/mdev = 1.880/2.035/2.190/0.155 ms
[root@v01-svn-test-server sysconfig]# service iptables status
Table: filter
Chain INPUT (policy DROP)
num target prot opt source destination
1 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:3306
2 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
3 ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp spt:53
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:22
5 ACCEPT all -- 127.0.0.1 127.0.0.1
6 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 Chain FORWARD (policy DROP)
num target prot opt source destination Chain OUTPUT (policy DROP)
num target prot opt source destination
1 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp spt:3306
2 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
3 ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:53
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp spt:22 state ESTABLISHED
5 ACCEPT all -- 127.0.0.1 0.0.0.0/0
6 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp spt:80 state ESTABLISHED