QIS client can't connect to QIS Server due to Firewall issues.

When using Artwork's QIS Client or when using your own client to connect to QIS, 
there may be cases where the client will not be able to connect to the QIS server.
It is usually due to firewall settings and it can be fixed if you follow the
instructions below...

Let's assume that QIS runs on Linux server. On the firewall settings of your Linux 
machine, you go to Main Menu/System Settings/Security Level, then select 
Enable Firewall or Disable Firewall.  If your setting is Enable Firewall, 
then that's why you have the socket connection issues from an external machine.

Firewall is good, now we just need to open up a port for QIS which you have 
already tried like this:

iptables -A INPUT -p tcp -i eth1 --dport 40000:50000 -j ACCEPT

However, there might be other "routing chains rules" as specified in the text file
 /etc/sysconfig/iptables.  For example, you may need to have 
"-A RH-Firewall-1-INPUT", instead of just "-A INPUT" because there is another routing 
rule in your iptables file like this:

-A INPUT -j RH-Firewall-1-INPUT

In that case, please take a look at the text file /etc/sysconfig/iptables and 
specify the -A correctly when running the program iptables.

Alternatively, settings can be added to the text file /etc/sysconfig/iptables, 
then restart the iptables service by going to Main Menu/System Settings/Server 
Settings/Services, then select iptables and click Restart.  The new settings 
are then shown in the panel on the right.  Double check if it shows the new settings.

You still need to explicitly specify -ip when running QIS:

qis -port 5001 -ip 123.456.789.10

Otherwise, QIS will start on the loopback address ( which only allows 
programs running on the same machine to connect to.  And you will then get the 
connection refused error when connecting from an external machine.