All the built-in functions (http_*() etc) can just connect to the current target of a scan as in general we have to make sure that the scanner is not connecting to hosts outside of the scanning scope.
Okay, thank you. So the “normal” functions are not available and I have to use “unsafe” functions (like pread). Do you know how to sign a custom-plugin to use the pread function? Using nasl -S plugin.nasl -o signed.nasl returns only an empty signed.nasl. Or is a log/verbose mode of nasl available? I would not like to use enable nasl_no_signature_check: yes.