Follow these steps to add a rule to iptables to allow incoming connections on port 9998:
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Edit iptables: # vi /etc/sysconfig/iptables
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Find the following line in the file:
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-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
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Add the following line BEFORE the above line:
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-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 9998 -j ACCEPT
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Restart iptables: # service iptables restart