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we just got a new server: CentOS 5, (linux) on 64 bit.

How do we see and change the firewall setting? - especially unblock PORT=8888 and PORT=9999 (for two java applets).

p.s. we've tried iptable - but without success.


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migrated from Jan 12 '12 at 16:16

This question came from our site for professional and enthusiast programmers.

What does this command show?

/sbin/iptables -L -v

To ensure it's not iptables blocking it, you could just run:

/sbin/service iptables stop

That way you know 100% that it isn't iptables. If you have verified iptables is stopped and the traffic still isn't getting through, I would recommend doing a tcpdump on that interface and specify those ports. This way you can see if the traffic is even hitting your server. If they are hitting the server and still being blocked, you need to verify you don't have any application specific filtering going on.

Edit: You also need to verify /etc/hosts.allow and /etc/hosts.deny to ensure the IP isn't blocked in there.

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use following, hit customized and put your port/proto in there

# system-config-firewall

don't forget to

# service iptables save

it will save all your current rules into /etc/sysconfig/iptables

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