Linux – How to run a command in another process’s network namespace

linuxnamespacesnetwork-namespace

There is a process running in its own network namespace. I would like to telnet to the machine and run a command in this process network namespace, something like that (17543 is the pid of the process with its own network namespace):

# ip netns exec /proc/17543/ns/net ifconfig
Cannot open network namespace "/proc/17543/ns/net": No such file or directory
# ls /proc/17543/ns/net
/proc/17543/ns/net

It complains that the network namespace is not there, but it looks that the file is there. How can I run a command in another process network namespace?

Best Answer

$ sudo nsenter -t 16882 -n ip link show

where ip link show is an example of a command to run in the network namespace of the target program with pid 16882.

-t flag is for specifying the target program's pid

-n flag stands for network namespace of the target program

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