Invalid users trying to log in to my server
I have a small ssh server mostly used for file sharing. A couple of other people and I use it and there are only 3 users. Recently I checked the auth.log file and there was a ridiculous amount of logins from a set of hosts with different usernames. I think I'm being hacked by something like hydra and I'm not sure what to do. I put a slice of the log file on pastebin: http://pastebin.com/Hgazhabu
I took some info out of the file for securities sake but everything you need to see is there. None of these usernames ring a bell nor does the ip.