Return port number or zero otherwise in forward command

[yotamN]

Fixes #456

[koral--]

Your PR does not pass the checks.

[denis99999]

It should not break backward compatibility

[yotamN]

I will make sure it passes the tests but regarding backward compatibility, I'm not sure how you want me to do it.
I must change the return value, so my options are:

• Create a new function and deprecate the old one, how would I call it?
• Keep returning null unless there's a port and than return the port (which is truthful)
• Extend the boolean object with getPort or something, the most awful solution IMO.