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asked Dec 4, 2020 at 14:53

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Create additional IP address in a separate network namespace

I'm running Ubuntu 18.04, Linux kernel 5.4.0. My laptop has local IP address 192.168.0.130:

$ sudo ip addr show dev wlp2s0 3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 7c:2a:31:09:3e:e0 brd ff:ff:ff:ff:ff:ff inet 192.168.0.130/24 brd 192.168.0.255 scope global dynamic noprefixroute wlp2s0 valid_lft 2782sec preferred_lft 2782sec inet6 fe80::b375:a43d:9705:556a/64 scope link noprefixroute valid_lft forever preferred_lft forever

The routing table looks like:

$ sudo ip route default via 192.168.0.1 dev wlp2s0 proto dhcp metric 600 169.254.0.0/16 dev wlp2s0 scope link metric 1000 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 192.168.0.0/24 dev wlp2s0 proto kernel scope link src 192.168.0.130 metric 600

I want to use an additional IP address visible for other hosts on the local network (e.g. 192.168.0.12). It works like this:

$ sudo ip addr add 192.168.0.95/24 dev wlp2s0 $ ssh 192.168.0.12 ping 192.168.0.95 ... 64 bytes from 192.168.0.95: ... (works) ^C $ sudo ip addr del 192.168.0.95/24 dev wlp2s0

Now, I want to move this IP address to a separate network namespace called net5, like this:

$ sudo ip netns add net5 $ sudo ip link add link wlp2s0 name net5in type macvlan $ sudo ip link set net5in netns net5 $ sudo ip netns exec net5 ip addr add 192.168.0.95/24 brd + dev net5in $ sudo ip netns exec net5 ip link set net5in up $ ssh 192.168.0.12 ping 192.168.0.95 ... From 192.168.0.95: ... Destination Host Unreachable (doesn't work) ^C $ sudo ip netns add net5

How can this be fixed so that the ping above works?

I was following these tutorials: