Hokay so...on my home network I'm running Ubuntu 12.04 LTS Server as a file server. I can SSH in and communicate with that server no problem. I have a home automation panel I wrote for the various devices on the network that was running on the file server. Since I have an older Lenovo Thinkpad SL410 with a broken screen lying around, I decided that I wanted to run the panel on the Thinkpad instead of the file server. So I installed Ubuntu 13.04 Desktop on the Lenovo. So far so good. The issue comes in that, for some reason unbeknownst to me, the file server can't communicate with the Lenovo. From my MacBook I can communicate with both. Since the MacBook is connected to the WiFi (as is the Lenovo) I can only surmise that it isn't an issue with the networking devices, but something with my config.
Here is a network diagram:
Just to reiterate: 10.0.0.247 can talk to both 10.0.0.200 and 10.0.0.201. However, 10.0.0.200 can't talk to 10.0.0.201 (and vice-versa).
I've made sure UFW is disabled (it's unnecessary internally). Pings fail with no routing errors, just 100% failure. SSH times out. Traceroute also never gets anyway.
Ask any clarifying questions and I'll do my best to answer them!
Edit: solved...a hard router reboot seems to have fixed it. Weird!