nc connection refused even on loopback

Question

I'm working on an embedded linux system, which appears to be networked correctly and is running ssh (dropbear) and rpcbind. I'm setting up a server application on it, and every single thing I try results in my connections being refused. Even the simplest thing like running nc -l 5566 on the device and running nc 192.168.1.129 5566 on my laptop results in a connection refused. Even sitting on the same device and running nc 127.0.0.1 5566 fails. I've tried multiple ports both above and below 1023

So, at the moment my guess is either iptables is getting in the way, or there's a limitation about running netcat as root that I don't know. (The device is single user, so root is the only login.) My iptables looks like this:

root@at91:~# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

It didn't print, but the INPUT chain is supposed to accept for anything on lo, eth0, and eth1.

I'm stumped. Any ideas? The device does not have SELinux.