I just installed Ubuntu Server on one of my computers. I use a Netgear router and it helped me to create a DynDNS account. I have a host name for my dynamic IP address and I have forwarded the ports to my computer's IP address. I can access my computer (Ubuntu Server) with HTTP, HTTPS, FTP and SSH from any remote computer.
Recently when I checked my router logs I found there are several remote computers that have connected to my servers SSH (port 22).
[LAN access from remote] from 188.8.131.52:43871 to 10.X.X.X:22 Monday, Sep 05,2011 04:10:19 [LAN access from remote] from 184.108.40.206:36664 to 10.X.X.X:22 Monday, Sep 05,2011 01:00:41
These IP addresses have tried to access my computer for more than an hour. There are several other IPs trying to do that also. When I logged into my SSH account I found no one has successfully logged in. Is my computer vulnerable? Or are these automated programs that are trying to make a connection, or is someone trying to hack my computer?