Linux Network Configuration Miscellaneous

11.211.2.1 ifcfg View Linux Routing entries

[[email protected] ~]# route -nKernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface10.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0

View system Activity Status Network interface information

[[email protected] ~]# ifconfigens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        inet 10.201.106.130  netmask 255.255.255.0  broadcast 10.201.106.255        inet6 fe80::20c:29ff:fea7:7aec  prefixlen 64  scopeid 0x20<link>        ether 00:0c:29:a7:7a:ec  txqueuelen 1000  (Ethernet)        RX packets 15514  bytes 17988974 (17.1 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 5902  bytes 1004507 (980.9 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536        inet 127.0.0.1  netmask 255.0.0.0        inet6 ::1  prefixlen 128  scopeid 0x10

Show all active and inactive interface information

[[email protected] ~]# ifconfig-aeth0 Link encap:ethernet HWaddr 00:0c:29:da:5a:22 inet addr:10.201  .106.129 bcast:10.201.106.255 mask:255.255.255.0 inet6 addr:fe80::20c:29ff:feda:5a22/64 scope:link up          Broadcast RUNNING multicast mtu:1500 metric:1 RX packets:14676 errors:0 dropped:0 overruns:0 frame:0 TX packets:10293 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:9260953  (8.8 MiB) TX bytes:1450866 (1.3 MiB) interrupt:19 Base address:0x2000 lo Link encap:local Loopback inet A          ddr:127.0.0.1 mask:255.0.0.0 Inet6 Addr::: 1/128 scope:host up LOOPBACK RUNNING mtu:65536 metric:1          RX packets:10 errors:0 dropped:0 overruns:0 frame:0           TX packets:10 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:568 (568.0 b) TX bytes:568 (568.0 b) pan0 Link encap:ethernet HWaddr 52:2c:94:69:6e:69 Inet6 addr:fe80::502c:94ff:fe69:6e69/64 scope:link up broadcast RUNNING multicast mtu:15          XX metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:592 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0  (0.0 b) TX bytes:200880 (196.1 KiB)

Display specified interface information

[[email protected] ~]# ifconfig eth0eth0      Link encap:Ethernet  HWaddr 00:0C:29:DA:5A:22            inet addr:10.201.106.129  Bcast:10.201.106.255  Mask:255.255.255.0          inet6 addr: fe80::20c:29ff:feda:5a22/64 Scope:Link          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1          RX packets:14707 errors:0 dropped:0 overruns:0 frame:0          TX packets:10322 errors:0 dropped:0 overruns:0 carrier:0          collisions:0 txqueuelen:1000           RX bytes:9263637 (8.8 MiB)  TX bytes:1454632 (1.3 MiB)          

Configure the eth0 address and mask and start

[[email protected] ~]# ifconfig eth0 10.201.106.129/24 up[[email protected] ~]# [[email protected] ~]# ifconfig eth0 10.201.106.129 netmask 255.255.255.0 up #第二种方法[[email protected] ~]# ifconfig eth0eth0      Link encap:Ethernet  HWaddr 00:0C:29:DA:5A:22            inet addr:10.201.106.129  Bcast:10.201.106.255  Mask:255.255.255.0          inet6 addr: fe80::20c:29ff:feda:5a22/64 Scope:Link          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1          RX packets:15000 errors:0 dropped:0 overruns:0 frame:0          TX packets:10544 errors:0 dropped:0 overruns:0 carrier:0          collisions:0 txqueuelen:1000           RX bytes:9290103 (8.8 MiB)  TX bytes:1479528 (1.4 MiB)          

No inverse display of routing table information

[[email protected] ~]# route -nKernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface10.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0

Adds a host route and specifies that the send from eth0

[[email protected] ~]# route add -host 192.168.1.3 gw 10.201.106.2 dev eth0[[email protected] ~]# route -nKernel IP routing table                  # Flags:条目标志位 U：启用状态，G：表示网关 H：主机路由Destination     Gateway         Genmask         Flags Metric Ref    Use Iface192.168.1.3     10.201.106.2    255.255.255.255 UGH   0      0        0 eth010.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0第二种方法[[email protected] ~]# route add default ge 10.201.106.2

Add Network Segment Routing

[[email protected] ~]# route add -net 192.168.0.0 netmask 255.255.255.0 gw 10.201.106.2 dev eth0[[email protected] ~]# route -nKernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface192.168.1.3     10.201.106.2    255.255.255.255 UGH   0      0        0 eth010.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0192.168.0.0     10.201.106.2    255.255.255.0   UG    0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0

Add a default route

[[email protected] ~]# route add -net 0.0.0.0 netmask 0.0.0.0 gw 10.201.106.2 dev eth0SIOCADDRT: 文件已存在[[email protected] ~]# route -nKernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface192.168.1.3     10.201.106.2    255.255.255.255 UGH   0      0        0 eth010.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0192.168.0.0     10.201.106.2    255.255.255.0   UG    0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0

Removing host routes

[[email protected] ~]# route del -host 192.168.1.3/32  gw 10.201.106.2[[email protected] ~]# route -nKernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface10.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0192.168.0.0     10.201.106.2    255.255.255.0   UG    0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0

Delete a network segment route

[[email protected] ~]# route del -net 192.168.0.0 netmask 255.255.255.0[[email protected] ~]# route -nKernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface10.201.106.0    0.0.0.0         255.255.255.0   U     0      0        0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG    0      0        0 eth0

11.2.2 DNS Modify system DNS address

[[email protected] ~]# vim /etc/resolv.conf ; generated by /sbin/dhclient-scriptsearch localdomainnameserver 10.201.106.2

Domain Name resolution

[[email protected] ~]# dig -t A www.qq.com; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.30.rc1.el6 <<>> -t A www.qq.com;; global options: +cmd;; Got answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12877;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0;; QUESTION SECTION:;www.qq.com.            IN  A;; ANSWER SECTION:www.qq.com.     5   IN  A   120.198.201.156;; Query time: 25 msec;; SERVER: 10.201.106.2#53(10.201.106.2);; WHEN: Wed Jul 20 18:19:45 2016;; MSG SIZE  rcvd: 44

Reverse parsing

[[email protected] ~]# dig -x 120.198.201.156

The host command forward and reverse parse

[[email protected] ~]# host -t A www.qq.comwww.qq.com has address 120.198.201.156[[email protected] ~]# [[email protected] ~]# host -t PTR 120.192.201.156Host 156.201.192.120.in-addr.arpa. not found: 3(NXDOMAIN)

11.2.3 netstat only shows TCP or UDP

[[email protected] ~]# netstat -tActive Internet connections (w/o servers)Proto Recv-Q Send-Q Local Address               Foreign Address             State      tcp        0      0 10.201.106.129:ssh          10.201.106.1:55907          ESTABLISHED tcp        0     52 10.201.106.129:ssh          10.201.106.1:56655          ESTABLISHED [[email protected] ~]# [[email protected] ~]# netstat -uActive Internet connections (w/o servers)Proto Recv-Q Send-Q Local Address               Foreign Address             State     

Do not do port reverse solution

[[email protected] ~]# netstat -tnActive Internet connections (w/o servers)Proto Recv-Q Send-Q Local Address               Foreign Address             State      tcp        0      0 10.201.106.129:22           10.201.106.1:55907          ESTABLISHED tcp        0     52 10.201.106.129:22           10.201.106.1:56655          

Displays all connections, including the monitored

[[email protected] ~]# netstat-tanactive Internet connections (servers and established) Proto recv-q send-q Local Add                   Ress Foreign Address State TCP 0 0 0.0.0.0:21 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 0 127.0.0.1:25 0.0.0.0:* LISTEN TCP 0 0 10.201.106.129:22 10.201.106.1:55907 ES tablished TCP 0 10.201.106.129:22 10.201.106.1:56655 established TCP 0 0::: 2                        2:::* LISTEN TCP 0 0:: 1:631:::*        LISTEN TCP 0 0:: 1:25:::* LISTEN TCP   0 0::: 80                    :::* LISTEN   

Show only the Listening connections

[[email protected] ~]# netstat -tnlActive Internet connections (only servers)Proto Recv-Q Send-Q Local Address               Foreign Address tcp        0      0 0.0.0.0:21                  0.0.0.0:*       tcp        0      0 0.0.0.0:22                  0.0.0.0:*       tcp        0      0 127.0.0.1:631               0.0.0.0:*       tcp        0      0 127.0.0.1:25                0.0.0.0:*       tcp        0      0 :::22                       :::*            tcp        0      0 ::1:631                     :::*            tcp        0      0 ::1:25                      :::*            tcp        0      0 :::80                       :::*     

Show Extended Properties

[[email protected] ~]# netstat -tnleActive Internet connections (only servers)Proto Recv-Q Send-Q Local Address               Foreign Address tcp        0      0 0.0.0.0:21                  0.0.0.0:*       tcp        0      0 0.0.0.0:22                  0.0.0.0:*       tcp        0      0 127.0.0.1:631               0.0.0.0:*       tcp        0      0 127.0.0.1:25                0.0.0.0:*       tcp        0      0 :::22                       :::*            tcp        0      0 ::1:631                     :::*            tcp        0      0 ::1:25                      :::*            tcp        0      

Displays the process and PID to which the connection belongs through the-p parameter

[[email protected] ~]# netstat-tnlpactive Internet connections (only servers) Proto recv-q send-q Local Address Foreign Address State Pid/program name TCP 0 0 0.0.0.0:21 0.0.0.                   0:* LISTEN 1438/vsftpd TCP 0 0 0.0.0.0:22 0.0.0.0:*       LISTEN 1425/sshd TCP 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1253/CUPSD TCP 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1550/mas ter TCP 0 0::: +:::* LISTEN 1425/sshd TC      P 0 0:: 1:631:::* LISTEN 1253/cupsd TCP 0                       0:: 1:25:::* LISTEN 1550/master TCP 0 0::: 80  :::*                      LISTEN 20471/httpd   

View the routing table

[[email protected] ~]# netstat -rnKernel IP routing tableDestination     Gateway         Genmask         Flags   MSS Window  irtt Iface10.201.106.0    0.0.0.0         255.255.255.0   U         0 0          0 eth00.0.0.0         10.201.106.2    0.0.0.0         UG        0 0          0 eth0

Display interface Statistics

[[email protected] ~]# netstat -Ieth0    #通过I选项指定接口统计信息Kernel Interface tableIface       MTU Met    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flgeth0       1500   0    18050      0      0      0    13229      0      0      0 BMRU[[email protected] ~]# netstat -i          #显示所有接口统计信息Kernel Interface tableIface       MTU Met    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flgeth0       1500   0    18064      0      0      0    13239      0      0      0 BMRUlo        65536   0       10      0      0      0       10      0      0      0 LRUpan0       1500   0        0      0      0      0      871      0      0      0 BMRU

Linux Network Configuration Miscellaneous