很多时候很多同学因为网络知识不熟悉不懂路由上不了网。其实路由很简单易学的
比如家里的路由器 网关是192.168.1.1 网段是192.168.0.0 ，你的IP 是192.168.1.10
如果你只要上网，你的电脑一条默认路由足够了
route add default gw 192.168.1.1

我们先来学与一下路由的基础命令route
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[root@localhost ~]# man route
ROUTE(8) Linux System Administrator's Manual ROUTE(8)

NAME
route - show / manipulate the IP routing table

SYNOPSIS
route [-CFvnNee] [-A family |-4|-6]

   route  [-v]  [-A  family |-4|-6] add [-net|-host] target [netmask Nm] [gw Gw] [metric N] [mss M] [window W]
          [irtt I] [reject] [mod] [dyn] [reinstate] [[dev] If]

   route  [-v] [-A family |-4|-6] del [-net|-host] target [gw Gw] [netmask Nm] [metric N] [[dev] If]

   route  [-V] [--version] [-h] [--help]

NOTE
This program is obsolete. For replacement check ip route.

DESCRIPTION
Route manipulates the kernel's IP routing tables. Its primary use is to set up static routes to specific
hosts or networks via an interface after it has been configured with the ifconfig(8) program.

   When the add or del options are used, route modifies the routing tables.  Without these options, route dis鈥[m
   plays the current contents of the routing tables.

OPTIONS
-A family
use the specified address family (eg `inet'). Use route --help for a full list. You can use -6 as an
alias for --inet6 and -4 as an alias for -A inet

   -F     operate on the kernel's FIB (Forwarding Information Base) routing table.  This is the default.

   -C     operate on the kernel's routing cache.

   -v     select verbose operation.

   -n     show  numerical  addresses instead of trying to determine symbolic host names. This is useful if you
          are trying to determine why the route to your nameserver has vanished.

   -e     use netstat(8)-format for displaying the routing table.  -ee will generate a very long line with all
          parameters from the routing table.

   del    delete a route.

   add    add a new route.

   target the  destination  network  or  host.  You can provide IP addresses in dotted decimal or host/network
          names.

   -net   the target is a network.

   -host  the target is a host.

   netmask NM
          when adding a network route, the netmask to be used.

   gw GW  route packets via a gateway.  NOTE: The specified gateway must  be  reachable  first.  This  usually
          means  that  you have to set up a static route to the gateway beforehand. If you specify the address
          of one of your local interfaces, it will be used to decide about the interface to which the  packets
          should be routed to. This is a BSDism compatibility hack.

   metric M
          set the metric field in the routing table (used by routing daemons) to M.

   mss M  sets  MTU (Maximum Transmission Unit) of the route to M bytes.  Note that the current implementation
          of the route command does not allow the option to set the Maximum Segment Size (MSS).

   window W
          set the TCP window size for connections over this route to W bytes. This is typically only  used  on
          AX.25 networks and with drivers unable to handle back to back frames.

   irtt I set  the  initial  round  trip  time  (irtt)  for  TCP connections over this route to I milliseconds
          (1-12000). This is typically only used on AX.25 networks. If omitted the RFC 1122 default  of  300ms
          is used.

   reject install a blocking route, which will force a route lookup to fail.  This is for example used to mask
          out networks before using the default route.  This is NOT for firewalling.

   mod, dyn, reinstate
          install a dynamic or modified route. These flags are for diagnostic purposes, and are generally only
          set by routing daemons.

   dev If force  the  route  to  be  associated with the specified device, as the kernel will otherwise try to
          determine the device on its own (by checking already existing routes and device specifications,  and
          where the route is added to). In most normal networks you won't need this.

          If  dev If is the last option on the command line, the word dev may be omitted, as it's the default.
          Otherwise the order of the route modifiers (metric - netmask - gw - dev) doesn't matter.

example
route add -net 127.0.0.0 netmask 255.0.0.0 dev lo
adds the normal loopback entry, using netmask 255.0.0.0 and associated with the "lo" device (assu
ing this device was previously set up correctly with ifconfig(8)).
添加正常环回条目，使用网络掩码 255.0.0.0 并与“lo”设备相关联, 之前使用 ifconfig(8) 正确设置了此设备。

   route add -net 192.56.76.0 netmask 255.255.255.0 dev eth0
          adds a route to the local network 192.56.76.x via "eth0".  The word "dev" can be omitted here.
          通过“eth0”添加到本地网络 192.56.76.x 的路由。这里可以省略“dev”这个词。
    
   route del default
          deletes the current default route, which is labeled "default" or 0.0.0.0 in the destination field of
          the current routing table.
          删除当前默认路由，在目标字段中标记为“默认”或 0.0.0.0 当前路由表。 

   route add default gw mango-gw
          adds a default route (which will be used if no other route matches).  All packets using  this  route
          will  be gatewayed through "mango-gw". The device which will actually be used for that route depends
          on how we can reach "mango-gw" - the static route to "mango-gw" will have to be set up before.
          添加默认路由（如果没有其他路由匹配，将使用该路由）。使用此路由的所有数据包
          将通过“mango-gw”作为网关。实际用于该路线的设备取决于
          关于我们如何到达“mango-gw” - 必须先设置到“mango-gw”的静态路由。
   route add ipx4 sl0
          Adds the route to the "ipx4" host via the SLIP interface (assuming that "ipx4" is the SLIP host).
          通过SLIP接口添加到“ipx4”主机的路由（假设“ipx4”是SLIP主机）
   route add -net 192.57.66.0 netmask 255.255.255.0 gw ipx4
          This command adds the net "192.57.66.x" to be gatewayed through the former route to the SLIP  inter
          face.
          该命令添加了要通过前一条路由到 SLIP 接口

   route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0
          This  is an obscure one documented so people know how to do it. This sets all of the class D (
          cast) IP routes to go via "eth0". This is the correct normal configuration line with a  multicasting
          kernel.
          这是一个晦涩的记录，因此人们知道如何去做。这将设置所有的 D 类（
          cast) IP 路由通过“eth0”。这是带有多播的正确正常配置行
          核心。

   route add -net 10.0.0.0 netmask 255.0.0.0 reject
          This installs a rejecting route for the private network "10.x.x.x."
            
          这将为专用网络“10.x.x.x”安装拒绝路由。

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