我正在尝试了解网络命名空间，并为此遵循此docker中的流程邮政创建它们。我创建了一个test命名空间并移至veth-b该命名空间，但似乎无法 ping 通192.168.3.1（请注意，它192.168.2.1工作正常）。接口似乎已启动，问题可能是什么？
sudo ip link add veth-a type veth peer name veth-b
$ ifconfig -a
<other_interfaces>
veth-a: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.2.1 netmask 255.255.255.0 broadcast 0.0.0.0
inet6 fe80::f057:76ff:fec4:5104 prefixlen 64 scopeid 0x20<link>
ether f2:57:76:c4:51:04 txqueuelen 1000 (Ethernet)
RX packets 12 bytes 936 (936.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 55 bytes 8117 (7.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
$ sudo ip netns exec test ifconfig -a
lo: flags=8<LOOPBACK> mtu 65536
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
veth-b: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.3.1 netmask 255.255.255.0 broadcast 0.0.0.0
inet6 fe80::58b9:ff:fecc:6fb5 prefixlen 64 scopeid 0x20<link>
ether 5a:b9:00:cc:6f:b5 txqueuelen 1000 (Ethernet)
RX packets 58 bytes 8762 (8.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 12 bytes 936 (936.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Ping 失败
$ ping 192.168.3.1
PING 192.168.3.1 (192.168.3.1) 56(84) bytes of data.
^C
--- 192.168.3.1 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2074ms
ping 成功
$ ping 192.168.2.1
PING 192.168.2.1 (192.168.2.1) 56(84) bytes of data.
64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=0.053 ms
64 bytes from 192.168.2.1: icmp_seq=2 ttl=64 time=0.043 ms
64 bytes from 192.168.2.1: icmp_seq=3 ttl=64 time=0.041 ms
64 bytes from 192.168.2.1: icmp_seq=4 ttl=64 time=0.049 ms
^C64 bytes from 192.168.2.1: icmp_seq=5 ttl=64 time=0.070 ms
$ ip route
default via 192.168.1.1 dev wlp4s0 proto dhcp src 192.168.1.138 metric 600
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
192.168.1.0/24 dev wlp4s0 proto kernel scope link src 192.168.1.138 metric 600
192.168.2.0/24 dev veth-a proto kernel scope link src 192.168.2.1
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
我尝试添加一条路线 sudo ip route add 192.168.3.0/24 dev veth-a但也没有帮助。
更新
在测试网络命名空间中启动后。我不知道为什么它会抱怨 192.168.2.1 无法访问。即使没有直接 ping 到，在博客中列出的正确阶段lo启动是否重要？lo
$ ping 192.168.3.1
PING 192.168.3.1 (192.168.3.1) 56(84) bytes of data.
From 192.168.2.1 icmp_seq=1 Destination Host Unreachable
From 192.168.2.1 icmp_seq=2 Destination Host Unreachable
From 192.168.2.1 icmp_seq=3 Destination Host Unreachable
From 192.168.2.1 icmp_seq=4 Destination Host Unreachable
From 192.168.2.1 icmp_seq=5 Destination Host Unreachable
From 192.168.2.1 icmp_seq=6 Destination Host Unreachable