Connection Refused

There could be many reasons, but the most common are:

1. The port is not open on the destination machine.
2. The port is open on the destination machine, but its backlog of pending connections is full.
3. A firewall between the client and server is blocking access (also check local firewalls).
4. IP address conflict

After checking for firewalls and that the port is open, use telnet to connect to the ip/port to test connectivity.
Test Connectivity
telnet 10.1.131.19 4447

Check the port status of remote system
netstat -tnlp | grep :4447

Check firewall
tcpdump -n icmp

Check IP
arping 10.1.131.19

Check the number of active connections
netstat -np | grep -w 4447 | grep ESTABLISHED | wc -l

 

Increasing the maximum number of tcp/ip connections in linux