环境：

• 树莓派通过网线连接laptop，走eth0网卡，用于ssh远程
• 树莓派连接wifi，走wlan0网卡，用于访问外网

需求：

• 现在要让树莓派同时连接两个网络，必须能通过wifi上外网，通过网线能用笔记本ssh远程

---

ip route是查看默认路由的

我们可以查看一下帮助

[root@oe-20-03-LTS ~]# ip route help
Usage: ip route { list | flush } SELECTORip route save SELECTORip route restoreip route showdumpip route get [ ROUTE_GET_FLAGS ] ADDRESS[ from ADDRESS iif STRING ][ oif STRING ] [ tos TOS ][ mark NUMBER ] [ vrf NAME ][ uid NUMBER ] [ ipproto PROTOCOL ][ sport NUMBER ] [ dport NUMBER ]ip route { add | del | change | append | replace } ROUTE
SELECTOR := [ root PREFIX ] [ match PREFIX ] [ exact PREFIX ][ table TABLE_ID ] [ vrf NAME ] [ proto RTPROTO ][ type TYPE ] [ scope SCOPE ]
ROUTE := NODE_SPEC [ INFO_SPEC ]
NODE_SPEC := [ TYPE ] PREFIX [ tos TOS ][ table TABLE_ID ] [ proto RTPROTO ][ scope SCOPE ] [ metric METRIC ][ ttl-propagate { enabled | disabled } ]
INFO_SPEC := { NH | nhid ID } OPTIONS FLAGS [ nexthop NH ]...
NH := [ encap ENCAPTYPE ENCAPHDR ] [ via [ FAMILY ] ADDRESS ][ dev STRING ] [ weight NUMBER ] NHFLAGS
FAMILY := [ inet | inet6 | mpls | bridge | link ]
OPTIONS := FLAGS [ mtu NUMBER ] [ advmss NUMBER ] [ as [ to ] ADDRESS ][ rtt TIME ] [ rttvar TIME ] [ reordering NUMBER ][ window NUMBER ] [ cwnd NUMBER ] [ initcwnd NUMBER ][ ssthresh NUMBER ] [ realms REALM ] [ src ADDRESS ][ rto_min TIME ] [ hoplimit NUMBER ] [ initrwnd NUMBER ][ features FEATURES ] [ quickack BOOL ] [ congctl NAME ][ pref PREF ] [ expires TIME ] [ fastopen_no_cookie BOOL ]
TYPE := { unicast | local | broadcast | multicast | throw |unreachable | prohibit | blackhole | nat }
TABLE_ID := [ local | main | default | all | NUMBER ]
SCOPE := [ host | link | global | NUMBER ]
NHFLAGS := [ onlink | pervasive ]
RTPROTO := [ kernel | boot | static | NUMBER ]
PREF := [ low | medium | high ]
TIME := NUMBER[s|ms]
BOOL := [1|0]
FEATURES := ecn
ENCAPTYPE := [ mpls | ip | ip6 | seg6 | seg6local ]
ENCAPHDR := [ MPLSLABEL | SEG6HDR ]
SEG6HDR := [ mode SEGMODE ] segs ADDR1,ADDRi,ADDRn [hmac HMACKEYID] [cleanup]
SEGMODE := [ encap | inline ]
ROUTE_GET_FLAGS := [ fibmatch ]
[root@oe-20-03-LTS ~]#

详细用法，可以参考一下上面的提示

---

然后我们现在要实现需求

• 先查看下默认路由
  ip route

[root@openEuler ~]# ip route
default via 192.168.2.1 dev eth0 proto static metric 100
default via 192.168.3.1 dev wlan0 proto dhcp metric 600
192.168.2.0/24 dev eth0 proto kernel scope link src 192.168.2.10 metric 100
192.168.3.0/24 dev wlan0 proto kernel scope link src 192.168.3.146 metric 600
[root@openEuler ~]# 

• 然后删掉默认的网线eth0的路由

[root@openEuler ~]# ip route del default via 192.168.2.1 dev eth0

• 然后再看下默认的路由

[root@openEuler ~]# ip route
default via 192.168.3.1 dev wlan0 proto dhcp metric 600
192.168.2.0/24 dev eth0 proto kernel scope link src 192.168.2.10 metric 100
192.168.3.0/24 dev wlan0 proto kernel scope link src 192.168.3.146 metric 600
[root@openEuler ~]#

然后就可以实现需求啦

打完收工！我们下期见！