I've setup an SSH server on my Ubuntu desktop at home using a dynamic DNS service (NOIP). I have a wi-fi-only Android tablet running Android version 4.4.2. On my tablet I can connect to other SSH servers, such as my college's server. However, I cannot directly connect from my tablet to my desktop; every attempt times out. But I am able to connect to my college's server and then SSH into my desktop from there. Is there something I've not set up correctly in my sshd_config file possibly? I'm able to ping the public IP. But I'm at a loss to explain this behavior. I've used both JuiceSSH and ConnectBot to no avail. Thanks!
Figured it out. The problem was that my router does not support connecting to forwarded ports on the WAN IP from inside the LAN. This explains why I was able to connect to my WAN IP from my college's server but was unable to connect when using the WAN IP on my local network.
edit: Unable to accept answer "until tomorrow."