网络排查常用命令：ping、traceroute、nslookup、dig、netstat，Linux命令举例

1、ping测试连通性，命令使用技巧，依次检查本地回环、本地IP、网关IP、外网IP

ping 127.0.0.1    ping回环，测试本地网络协议是否正常

[jiaozn@itman ~]$ ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.075 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.074 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.074 ms
64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.066 ms
64 bytes from 127.0.0.1: icmp_seq=5 ttl=64 time=0.062 ms
^C
--- 127.0.0.1 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4025ms
rtt min/avg/max/mdev = 0.062/0.070/0.075/0.007 ms

2、traceroute路由跟踪 默认UDP封装跟中包，加-I选项使用ICMP封装

[root@itman ~]# traceroute -I www.jiaozn.com
traceroute to www.jiaozn.com (114.215.132.189), 30 hops max, 60 byte packets
 1  172.16.1.1 (172.16.1.1)  2.952 ms  2.939 ms  5.514 ms
 2  * * *
 3  * * *
 4  * * *
 5  * * *
 6  * * *
 7  * * *
 8  * * *
 9  * * *
10  ip215.hichina.com (114.215.132.189)  168.283 ms  168.311 ms  168.303 ms

3、nslookup测试本地设置的DNS服务器是否正常，查询域名与IP地址之间的对应关系

[root@itman ~]# nslookup www.d7it.com
Server:        172.16.1.1
Address:    172.16.1.1#53

Non-authoritative answer:
Name:    www.d7it.com
Address: 114.215.132.189

4、dig查询更多关于DNS记录的信息，查看MX（邮件记录）、NS（域名服务器记录）等信息

[root@itman ~]# dig www.jiaozn.com

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> www.jiaozn.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7236
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 8

;; QUESTION SECTION:
;www.jiaozn.com.            IN    A

;; ANSWER SECTION:
www.jiaozn.com.        31    IN    A    114.215.132.189

;; AUTHORITY SECTION:
jiaozn.com.        31    IN    NS    f1g1ns1.dnspod.net.
jiaozn.com.        31    IN    NS    f1g1ns2.dnspod.net.

;; ADDITIONAL SECTION:
f1g1ns1.dnspod.net.    124617    IN    A    182.140.167.166
f1g1ns1.dnspod.net.    124617    IN    A    183.60.52.217
f1g1ns1.dnspod.net.    124617    IN    A    119.167.195.3
f1g1ns1.dnspod.net.    124617    IN    A    122.225.217.192
f1g1ns2.dnspod.net.    124617    IN    A    182.140.167.188
f1g1ns2.dnspod.net.    124617    IN    A    112.90.143.29
f1g1ns2.dnspod.net.    124617    IN    A    122.225.217.191
f1g1ns2.dnspod.net.    124617    IN    A    180.153.162.150

;; Query time: 37 msec
;; SERVER: 172.16.1.1#53(172.16.1.1)
;; WHEN: Sat Jul 12 22:25:35 2014
;; MSG SIZE  rcvd: 230

[root@itman ~]# dig www.itq.im MX    #查看itq.im的邮件记录
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6 <<>> www.itq.im MX
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61505
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.itq.im.            IN    MX

;; AUTHORITY SECTION:
itq.im.            31    IN    SOA    f1g1ns1.dnspod.net. freednsadmin.dnspod.com. 1404882498 3600 180 1209600 180

;; Query time: 22 msec
;; SERVER: 172.16.1.1#53(172.16.1.1)
;; WHEN: Sat Jul 12 22:45:00 2014
;; MSG SIZE  rcvd: 105

5、netstat查看网络链接状态、端口

netstat -an        #查看网络链接状态

netstat -nutlp    #查看当前系统开启的端口信息