iptables couldn't load target

Question

I am getting this error

iptables v1.6.0: Couldn't load target `standard':No such file or directory

Any idea why, and how to solve? The debian version is 9.1

(venv)root@deb64:/tmp# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
iptables v1.6.0: Couldn't load target `standard':No such file or directory

Try `iptables -h' or 'iptables --help' for more information.

Solution

The iptables command comes with a whole set of libraries that match the modules, the targets, etc. A message like "Couldn't load target 'FOO'" typically means that the dynamic library corresponding to the target FOO (iptables -j FOO) was not found.

But this message is misleading. Debian iptables actually comes with a libxt_standard.so library and the error message probably means that the library is missing on your machine:

# dpkg -L iptables | fgrep standard
/usr/lib/x86_64-linux-gnu/xtables/libxt_standard.so

You should probably reinstall iptables:

apt-get install --reinstall iptables