Sending message from one router to another in a mesh network

I'm trying to send a message from one router to another in a mesh network using netcat but the server router and client router is not getting connected and shows "connection refused".
I followed this link:
I'm new to netcat so it would be a great help if you could guide me.
thanks in advance.

Do the routers have reachable IP addresses from each other? ping is a quick way to confirm that.

thanks for replying.
yes I'm able to ping

You need a "listener" on one host, then you can nc from a different host to that target.

If you're having problems, check netstat -anl to see if you've got a listener running. Also, tcpdump-mini will supply tcpdump, which is the "standard" tool for checking to see if packets are arriving/leaving as you expect.

Ip address of the other router is but I couldn't find it when I used netstat -anlnet

It doesn't look like you've started the listener on that machine. I only see listeners on ports 80, 53, and 22 (Look under "Local Address" where "State" is "LISTEN")

Firewall issue?

If these routers are connected via what is considered their WAN interface, nearly everything is going to be blocked by default.

While firewall rules might be another source of problems, in this case the listener isn't even started (netstat just displays which ports are bound to a binary, regardless of their firewalling state).

In the server router (of ip address in order to set it to listen to 3333 port, I used the following code
$ nc -l 3333
And in client router (of ip address , I used the following code
$ nc 3333
still I'm getting the same output when I type netstat -anl
what should i do to start the listener?