There's some misleading information in --help and ss(8) manpage about
TCP-STATE named 'listen'.
ss doesn't know such a state, but it knows 'listening' state.
$ ss -tua state listen
ss: wrong state name: listen
$ ss -tua state listening
[...]
Addresses: https://bugs.debian.org/872990
Reported-by: Pavel Lyulchenko <p.lyulchenko@gmail.com>
Signed-off-by: Andreas Henriksson <andreas@fatal.se>