I think it's either one of those things that's against the rules but not really enforced, or it's one of those things that's not disallowed but is heavily frowned upon.
Disclaimer: I am NOT a legal expert, nor am i an expert on Minecraft's EULA, my knowledge of this subject is rather lacking
debug.log is a text file, my signature explains where to find it (the .minecraft is a link to the Minecraft Wiki page that will tell you where to find .minecraft depending on your operating system) and has links to the sites we would prefer you used to post it.
How about you make a dedicated server folder on your desktop and do all this in there? It's easier to get to and keeps server and client separate.
Make the folder, put the server jar in it, then point the installer to the folder.
debug.log is a file generated by a Forge client or server, it contains more detail about what happens behind the scenes. My signature has instructions on where to find it and links to the sites that we would prefer you used to post it.