Linux实战命令之一：网络基本配置
一、设置IP
我们可以为网卡设置固定的IP，也可设置一个用于测试的临时IP。要设置一个固定IP，可以通过命令setup和netconfig或通过修过配置文件来完成。
1、本例我们假设已配置了第1个网卡的IP，将为第2个网卡配置IP地址。过程如下：
[root@OracleOnLinux root]# cd /etc/sysconfig/network-scripts/
[root@OracleOnLinux network-scripts]# ls //查看当前目录中的文件，可以看到没有第2个网卡的配置文件
ifcfg-eth0 ifdown-ipv6 ifup ifup-isdn ifup-sit
ifcfg-lo ifdown-isdn ifup-aliases ifup-plip ifup-sl
ifdown ifdown-post ifup-cipcb ifup-plusb ifup-wireless
ifdown-aliases ifdown-ppp ifup-ippp ifup-post init.ipv6-global
ifdown-cipcb ifdown-sit ifup-ipv6 ifup-ppp network-functions
ifdown-ippp ifdown-sl ifup-ipx ifup-routes network-functions-ipv6
[root@OracleOnLinux network-scripts]# cat ifcfg-eth0 //通过配置文件查看eth0的配置
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.154
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
[root@OracleOnLinux network-scripts]# cp ifcfg-eth0 ifcfg-eth1 //拷贝一份以建立第二个网卡eth1的配置文件
[root@OracleOnLinux network-scripts]# vi ifcfg-eth1 //修改原配置文件为以下内容
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=static
IPADDR=172.16.0.254
NETMASK=255.255.255.0
GATEWAY=172.16.0.1
~
"ifcfg-eth1" [已转换] 6L, 101C 已写入
[root@OracleOnLinux network-scripts]# service network restart //重启网络服务，使修改生效
正在关闭接口 eth0： [ 确定 ]
正在关闭接口 eth1： [ 确定 ]
关闭环回接口： [ 确定 ]
设置网络参数： [ 确定 ]
弹出环回接口： [ 确定 ]
弹出界面 eth0： [ 确定 ]
弹出界面 eth1： [ 确定 ]
[root@OracleOnLinux network-scripts]# ifconfig //查看当前IP的配置，可见第二个网卡的IP已配置成功
eth0 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:963 errors:0 dropped:0 overruns:0 frame:0
TX packets:664 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:87678 (85.6 Kb) TX bytes:67862 (66.2 Kb)
Interrupt:10 Base address:0x1080
eth1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:8A
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:192 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:15035 (14.6 Kb) TX bytes:168 (168.0 b)
Interrupt:9 Base address:0x1400
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:20 errors:0 dropped:0 overruns:0 frame:0
TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1618 (1.5 Kb) TX bytes:1618 (1.5 Kb)
[root@OracleOnLinux network-scripts]# ifconfig | grep inet //只查看IP部分
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
inet addr:127.0.0.1 Mask:255.0.0.0
2、现在我们来设置一个临时用于测试的IP
[root@OracleOnLinux network-scripts]# ifconfig eth0:1 10.0.0.254 netmask 255.255.255.0 //对eth0再分配一个临时IP
[root@OracleOnLinux network-scripts]# ifconfig | more
eth0 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
……
eth0:1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80 //可见临时IP已设置好
inet addr:10.0.0.254 Bcast:10.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:269 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:20922 (20.4 Kb) TX bytes:168 (168.0 b)
Interrupt:10 Base address:0x1080
eth1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:8A
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
……
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
……
[root@OracleOnLinux network-scripts]# service network restart //重启网络服务
[root@OracleOnLinux network-scripts]# ifconfig | more //再次查看设置的临时IP已消失
eth0 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
……
eth1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:8A
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
……
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
……
===================================================================================================
二、设置路由
1、查看本地路由
[root@linux-tys root]# netstat -rn //查看本机路由表，也可用route命令
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
172.16.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
12.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 12.0.0.254 0.0.0.0 UG 0 0 0 eth0
2、添加一条路由
[root@linux-tys root]# route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.0.154 dev eth0 //添加一个网络路由
[root@linux-tys root]# route add -host 172.16.0.169 gw 172.16.0.254 //添加一个主机路由
[root@linux-tys root]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
172.16.0.169 172.16.0.254 255.255.255.255 UGH 0 0 0 eth1
192.168.3.0 192.168.0.154 255.255.255.0 UG 0 0 0 eth0
172.16.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
12.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 12.0.0.254 0.0.0.0 UG 0 0 0 eth0
---------------------------------
注：
Flags：路由标志。其中U表示路由项是活动的；H表示目标为单个主机；G表示使用网关；R表对动态路由进行修复；D表示路由项是动态安装的；M表示动态修改路由；！表示拒绝路由。
Ref：依赖于本路由的其它路由数目。
Use：该路由项被使用的次数。
Iface：该路由项发送数据包使用的网络接口。
-------------------------------------------------------
[root@linux-tys root]# route del -net 192.168.3.0 netmask 255.255.255.0 //删除网络路由
[root@linux-tys root]# route del -host 172.16.0.169 //删除主机路由
[root@linux-tys root]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
172.16.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
12.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 12.0.0.254 0.0.0.0 UG 0 0 0 eth0
三、用命令ping测试网络连通性
[root@linux-tys root]# ping 192.168.0.16 //本命令需用用ctrl+c中止
PING 192.168.0.16 (192.168.0.16) 56(84) bytes of data.
64 bytes from 192.168.0.16: icmp_seq=1 ttl=64 time=0.550 ms
64 bytes from 192.168.0.16: icmp_seq=2 ttl=64 time=0.341 ms
64 bytes from 192.168.0.16: icmp_seq=3 ttl=64 time=0.222 ms
64 bytes from 192.168.0.16: icmp_seq=4 ttl=64 time=0.220 ms
64 bytes from 192.168.0.16: icmp_seq=5 ttl=64 time=0.208 ms
64 bytes from 192.168.0.16: icmp_seq=6 ttl=64 time=0.274 ms
--- 192.168.0.16 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5095ms
rtt min/avg/max/mdev = 0.208/0.302/0.550/0.120 ms
[root@linux-tys root]# ping --help //查看帮助
ping: invalid option -- -
Usage: ping [-LRUbdfnqrvVaA] [-c count] [-i interval] [-w deadline]
[-p pattern] [-s packetsize] [-t ttl] [-I interface or address]
[-M mtu discovery hint] [-S sndbuf]
[ -T timestamp option ] [ -Q tos ] [hop1 ...] destination
[root@linux-tys root]# ping -c 4 -s 1000 192.168.0.16
PING 192.168.0.16 (192.168.0.16) 1000(1028) bytes of data.
1008 bytes from 192.168.0.16: icmp_seq=1 ttl=64 time=0.314 ms
1008 bytes from 192.168.0.16: icmp_seq=2 ttl=64 time=0.251 ms
1008 bytes from 192.168.0.16: icmp_seq=3 ttl=64 time=0.231 ms
1008 bytes from 192.168.0.16: icmp_seq=4 ttl=64 time=0.233 ms
--- 192.168.0.16 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3058ms
rtt min/avg/max/mdev = 0.231/0.257/0.314/0.035 ms
四、命令netstat的使用
1、netstat命令常用参数简介
1） �Ct 显示当前TCP协议连接情况
2） �Cl 查看系统监听情况
3）�Cln 同上，但将以数字形式表示端口信息
4）netstat �Ci 查看网卡传送、接收数据包的情况
5） �Can 查看所有连接，并以数字形式表示端口信息
6） �Cr 查看本机的路由
2、netstat命令使用示例
[root@linux-tys root]# netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 127.0.0.1:1024 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:1025 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:10000 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 52 192.168.0.154:22 192.168.0.16:1059 ESTABLISHED
tcp 0 0 192.168.0.154:22 192.168.0.16:1049 ESTABLISHED
udp 0 0 0.0.0.0:1024 0.0.0.0:*
udp 0 0 0.0.0.0:10000 0.0.0.0:*
udp 0 0 0.0.0.0:846 0.0.0.0:*
udp 0 0 0.0.0.0:111 0.0.0.0:*
udp 0 0 0.0.0.0:631 0.0.0.0:*
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 8474 /tmp/.esd/socket
unix 13 [ ] DGRAM 1580 /dev/log
unix 2 [ ACC ] STREAM LISTENING 7552 /tmp/.fam_socket
unix 2 [ ACC ] STREAM LISTENING 2161 /tmp/.font-unix/fs7100
unix 2 [ ACC ] STREAM LISTENING 8553 /tmp/ssh-XXVkjhRL/agent.4243
unix 2 [ ACC ] STREAM LISTENING 6092 /tmp/ssh-XXG3eSwq/agent.3773
unix 2 [ ] STREAM 8473
unix 3 [ ] STREAM CONNECTED 7727 /tmp/.famaJaaeu
unix 3 [ ] STREAM CONNECTED 7726
unix 2 [ ] DGRAM 5428
unix 2 [ ] DGRAM 5165
unix 2 [ ] DGRAM 4860
unix 2 [ ] DGRAM 2237
unix 2 [ ] DGRAM 2192
unix 2 [ ] DGRAM 2179
unix 2 [ ] DGRAM 2055
unix 2 [ ] DGRAM 2013
unix 2 [ ] DGRAM 1771
unix 2 [ ] DGRAM 1630
unix 2 [ ] DGRAM 1595
[root@linux-tys root]# netstat -t
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 tys.linux.com:ssh 192.168.0.16:1059 ESTABLISHED
tcp 0 0 tys.linux.com:ssh 192.168.0.16:1049 ESTABLISHED
[root@linux-tys root]#
-----待续--------
我们可以为网卡设置固定的IP，也可设置一个用于测试的临时IP。要设置一个固定IP，可以通过命令setup和netconfig或通过修过配置文件来完成。
1、本例我们假设已配置了第1个网卡的IP，将为第2个网卡配置IP地址。过程如下：
[root@OracleOnLinux root]# cd /etc/sysconfig/network-scripts/
[root@OracleOnLinux network-scripts]# ls //查看当前目录中的文件，可以看到没有第2个网卡的配置文件
ifcfg-eth0 ifdown-ipv6 ifup ifup-isdn ifup-sit
ifcfg-lo ifdown-isdn ifup-aliases ifup-plip ifup-sl
ifdown ifdown-post ifup-cipcb ifup-plusb ifup-wireless
ifdown-aliases ifdown-ppp ifup-ippp ifup-post init.ipv6-global
ifdown-cipcb ifdown-sit ifup-ipv6 ifup-ppp network-functions
ifdown-ippp ifdown-sl ifup-ipx ifup-routes network-functions-ipv6
[root@OracleOnLinux network-scripts]# cat ifcfg-eth0 //通过配置文件查看eth0的配置
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.154
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
[root@OracleOnLinux network-scripts]# cp ifcfg-eth0 ifcfg-eth1 //拷贝一份以建立第二个网卡eth1的配置文件
[root@OracleOnLinux network-scripts]# vi ifcfg-eth1 //修改原配置文件为以下内容
DEVICE=eth1
ONBOOT=yes
BOOTPROTO=static
IPADDR=172.16.0.254
NETMASK=255.255.255.0
GATEWAY=172.16.0.1
~
"ifcfg-eth1" [已转换] 6L, 101C 已写入
[root@OracleOnLinux network-scripts]# service network restart //重启网络服务，使修改生效
正在关闭接口 eth0： [ 确定 ]
正在关闭接口 eth1： [ 确定 ]
关闭环回接口： [ 确定 ]
设置网络参数： [ 确定 ]
弹出环回接口： [ 确定 ]
弹出界面 eth0： [ 确定 ]
弹出界面 eth1： [ 确定 ]
[root@OracleOnLinux network-scripts]# ifconfig //查看当前IP的配置，可见第二个网卡的IP已配置成功
eth0 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:963 errors:0 dropped:0 overruns:0 frame:0
TX packets:664 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:87678 (85.6 Kb) TX bytes:67862 (66.2 Kb)
Interrupt:10 Base address:0x1080
eth1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:8A
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:192 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:15035 (14.6 Kb) TX bytes:168 (168.0 b)
Interrupt:9 Base address:0x1400
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:20 errors:0 dropped:0 overruns:0 frame:0
TX packets:20 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1618 (1.5 Kb) TX bytes:1618 (1.5 Kb)
[root@OracleOnLinux network-scripts]# ifconfig | grep inet //只查看IP部分
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
inet addr:127.0.0.1 Mask:255.0.0.0
2、现在我们来设置一个临时用于测试的IP
[root@OracleOnLinux network-scripts]# ifconfig eth0:1 10.0.0.254 netmask 255.255.255.0 //对eth0再分配一个临时IP
[root@OracleOnLinux network-scripts]# ifconfig | more
eth0 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
……
eth0:1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80 //可见临时IP已设置好
inet addr:10.0.0.254 Bcast:10.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:269 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:20922 (20.4 Kb) TX bytes:168 (168.0 b)
Interrupt:10 Base address:0x1080
eth1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:8A
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
……
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
……
[root@OracleOnLinux network-scripts]# service network restart //重启网络服务
[root@OracleOnLinux network-scripts]# ifconfig | more //再次查看设置的临时IP已消失
eth0 Link encap:Ethernet HWaddr 00:0C:29:2E:70:80
inet addr:192.168.0.154 Bcast:192.168.0.255 Mask:255.255.255.0
……
eth1 Link encap:Ethernet HWaddr 00:0C:29:2E:70:8A
inet addr:172.16.0.254 Bcast:172.16.0.255 Mask:255.255.255.0
……
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
……
===================================================================================================
二、设置路由
1、查看本地路由
[root@linux-tys root]# netstat -rn //查看本机路由表，也可用route命令
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
172.16.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
12.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 12.0.0.254 0.0.0.0 UG 0 0 0 eth0
2、添加一条路由
[root@linux-tys root]# route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.0.154 dev eth0 //添加一个网络路由
[root@linux-tys root]# route add -host 172.16.0.169 gw 172.16.0.254 //添加一个主机路由
[root@linux-tys root]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
172.16.0.169 172.16.0.254 255.255.255.255 UGH 0 0 0 eth1
192.168.3.0 192.168.0.154 255.255.255.0 UG 0 0 0 eth0
172.16.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
12.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 12.0.0.254 0.0.0.0 UG 0 0 0 eth0
---------------------------------
注：
Flags：路由标志。其中U表示路由项是活动的；H表示目标为单个主机；G表示使用网关；R表对动态路由进行修复；D表示路由项是动态安装的；M表示动态修改路由；！表示拒绝路由。
Ref：依赖于本路由的其它路由数目。
Use：该路由项被使用的次数。
Iface：该路由项发送数据包使用的网络接口。
-------------------------------------------------------
[root@linux-tys root]# route del -net 192.168.3.0 netmask 255.255.255.0 //删除网络路由
[root@linux-tys root]# route del -host 172.16.0.169 //删除主机路由
[root@linux-tys root]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
172.16.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
12.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 192.168.0.254 0.0.0.0 UG 0 0 0 eth0
0.0.0.0 12.0.0.254 0.0.0.0 UG 0 0 0 eth0
三、用命令ping测试网络连通性
[root@linux-tys root]# ping 192.168.0.16 //本命令需用用ctrl+c中止
PING 192.168.0.16 (192.168.0.16) 56(84) bytes of data.
64 bytes from 192.168.0.16: icmp_seq=1 ttl=64 time=0.550 ms
64 bytes from 192.168.0.16: icmp_seq=2 ttl=64 time=0.341 ms
64 bytes from 192.168.0.16: icmp_seq=3 ttl=64 time=0.222 ms
64 bytes from 192.168.0.16: icmp_seq=4 ttl=64 time=0.220 ms
64 bytes from 192.168.0.16: icmp_seq=5 ttl=64 time=0.208 ms
64 bytes from 192.168.0.16: icmp_seq=6 ttl=64 time=0.274 ms
--- 192.168.0.16 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5095ms
rtt min/avg/max/mdev = 0.208/0.302/0.550/0.120 ms
[root@linux-tys root]# ping --help //查看帮助
ping: invalid option -- -
Usage: ping [-LRUbdfnqrvVaA] [-c count] [-i interval] [-w deadline]
[-p pattern] [-s packetsize] [-t ttl] [-I interface or address]
[-M mtu discovery hint] [-S sndbuf]
[ -T timestamp option ] [ -Q tos ] [hop1 ...] destination
[root@linux-tys root]# ping -c 4 -s 1000 192.168.0.16
PING 192.168.0.16 (192.168.0.16) 1000(1028) bytes of data.
1008 bytes from 192.168.0.16: icmp_seq=1 ttl=64 time=0.314 ms
1008 bytes from 192.168.0.16: icmp_seq=2 ttl=64 time=0.251 ms
1008 bytes from 192.168.0.16: icmp_seq=3 ttl=64 time=0.231 ms
1008 bytes from 192.168.0.16: icmp_seq=4 ttl=64 time=0.233 ms
--- 192.168.0.16 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3058ms
rtt min/avg/max/mdev = 0.231/0.257/0.314/0.035 ms
四、命令netstat的使用
1、netstat命令常用参数简介
1） �Ct 显示当前TCP协议连接情况
2） �Cl 查看系统监听情况
3）�Cln 同上，但将以数字形式表示端口信息
4）netstat �Ci 查看网卡传送、接收数据包的情况
5） �Can 查看所有连接，并以数字形式表示端口信息
6） �Cr 查看本机的路由
2、netstat命令使用示例
[root@linux-tys root]# netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 127.0.0.1:1024 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:1025 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:10000 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 52 192.168.0.154:22 192.168.0.16:1059 ESTABLISHED
tcp 0 0 192.168.0.154:22 192.168.0.16:1049 ESTABLISHED
udp 0 0 0.0.0.0:1024 0.0.0.0:*
udp 0 0 0.0.0.0:10000 0.0.0.0:*
udp 0 0 0.0.0.0:846 0.0.0.0:*
udp 0 0 0.0.0.0:111 0.0.0.0:*
udp 0 0 0.0.0.0:631 0.0.0.0:*
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 8474 /tmp/.esd/socket
unix 13 [ ] DGRAM 1580 /dev/log
unix 2 [ ACC ] STREAM LISTENING 7552 /tmp/.fam_socket
unix 2 [ ACC ] STREAM LISTENING 2161 /tmp/.font-unix/fs7100
unix 2 [ ACC ] STREAM LISTENING 8553 /tmp/ssh-XXVkjhRL/agent.4243
unix 2 [ ACC ] STREAM LISTENING 6092 /tmp/ssh-XXG3eSwq/agent.3773
unix 2 [ ] STREAM 8473
unix 3 [ ] STREAM CONNECTED 7727 /tmp/.famaJaaeu
unix 3 [ ] STREAM CONNECTED 7726
unix 2 [ ] DGRAM 5428
unix 2 [ ] DGRAM 5165
unix 2 [ ] DGRAM 4860
unix 2 [ ] DGRAM 2237
unix 2 [ ] DGRAM 2192
unix 2 [ ] DGRAM 2179
unix 2 [ ] DGRAM 2055
unix 2 [ ] DGRAM 2013
unix 2 [ ] DGRAM 1771
unix 2 [ ] DGRAM 1630
unix 2 [ ] DGRAM 1595
[root@linux-tys root]# netstat -t
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 tys.linux.com:ssh 192.168.0.16:1059 ESTABLISHED
tcp 0 0 tys.linux.com:ssh 192.168.0.16:1049 ESTABLISHED
[root@linux-tys root]#
-----待续--------