一、拓扑图

新加核心交换机在分中心，分别连区域中心上传路段视频，和路由器去映射内网手机发布服务器，远程手机查看视频，内网服务器必须上网。

二、问题描述

  现在分中心上传区域中心视频正常，手机发布服务器不能上网，手机无法远程观看视频。

三、解决方案

  查看核心交换机的静态路由器，发现默认路由指向区域分中心。核心交换机与路由器之间互联可以相互ping通，就是无法上网。

  发现所有上网请求都被发往区域中心（默认路由的作用），增加一条指向路由器的默认路由，修改优先级为50，（默认60）

  配置代码如下：

[GLZX_hexin_s5700]ip route-static 0.0.0.0 0.0.0.0 172.16.10.1 preference 50

[GLZX_hexin_s5700]ping 218.30.67.83 （上网正常）

  PING 218.30.67.83: 56  data bytes, press CTRL_C to break

    Reply from 218.30.67.83: bytes=56 Sequence=1 ttl=120 time=49 ms

    Reply from 218.30.67.83: bytes=56 Sequence=2 ttl=120 time=49 ms

    Reply from 218.30.67.83: bytes=56 Sequence=3 ttl=120 time=49 ms

    Reply from 218.30.67.83: bytes=56 Sequence=4 ttl=120 time=49 ms

    Reply from 218.30.67.83: bytes=56 Sequence=5 ttl=120 time=48 ms

  --- 218.30.67.83 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 48/48/49 ms

[GLZX_hexin_s5700]quit

<GLZX_hexin_s5700>sa

<GLZX_hexin_s5700>save （保存）

The current configuration will be written to the device.

Are you sure to continue?[Y/N]y

Now saving the current configuration to the slot 0.

Save the configuration successfully.

<GLZX_hexin_s5700>ping www.baidu.com (域名ping不通)

Error: Unknown host www.baidu.com.

<GLZX_hexin_s5700>sys

<GLZX_hexin_s5700>system-view 

Enter system view, return user view with Ctrl+Z.

[GLZX_hexin_s5700]dns server 118.118.118.9 （设置DNS）

[GLZX_hexin_s5700]

[GLZX_hexin_s5700]dns resolve （启用解析）

[GLZX_hexin_s5700]ping www.baidu.com  （百度正常）

  PING www.a.shifen.com (14.215.177.38): 56  data bytes, press CTRL_C to break

    Reply from 14.215.177.38: bytes=56 Sequence=1 ttl=55 time=33 ms

    Reply from 14.215.177.38: bytes=56 Sequence=2 ttl=55 time=33 ms

    Reply from 14.215.177.38: bytes=56 Sequence=3 ttl=55 time=33 ms

    Reply from 14.215.177.38: bytes=56 Sequence=4 ttl=55 time=33 ms

    Reply from 14.215.177.38: bytes=56 Sequence=5 ttl=55 time=33 ms

  --- www.a.shifen.com ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 33/33/33 ms

[GLZX_hexin_s5700]clock timezone BJ add 8   （设置时区）

[GLZX_hexin_s5700]dis ntp-service status    （查看NTP状态）

 clock status: unsynchronized 

 clock stratum: 16 

 reference clock ID: none

 nominal frequency: 60.0002 Hz 

 actual frequency: 60.0002 Hz 

 clock precision: 2^17

 clock offset: 0.0000 ms 

 root delay: 0.00 ms 

 root dispersion: 0.00 ms 

 peer dispersion: 0.00 ms 

 reference time: 00:00:00.000 UTC Jan 1 1900(00000000.00000000)

[GLZX_hexin_s5700]ntp-service unicast-server 202.120.2.101             

[GLZX_hexin_s5700]

Oct  1 2008 16:37:58+08:00 GLZX_hexin_s5700 %%01NTP/4/PEER_SELE(l)[2]:The peer selected by the system is 202.120.2.101.

[GLZX_hexin_s5700]dis clock   （显示时间，发现时间已经校准）                              

2016-12-21 12:48:13+08:00

Wednesday

Time Zone(BJ) : UTC+08:00

[GLZX_hexin_s5700]quit

<GLZX_hexin_s5700>save

The current configuration will be written to the device.

Are you sure to continue?[Y/N]y

Dec 21 2016 12:48:34+08:00 GLZX_hexin_s5700 %%01CFM/4/SAVE(l)[5]:The user chose Y when deciding whether to save the configuration to the device.

Now saving the current configuration to the slot 0..

Save the configuration successfully.

<GLZX_hexin_s5700>

至此，问题解决。

本文出自 “技术成就未来” 博客，请务必保留此出处http://linuxmysqldba.blog.51cto.com/2530817/1885080

S5700三层交换机 复杂网络环境设置默认路优先级实战