Linux in EC2(Amazon) cannot use port 80 for tomcat

amazon-ec2, amazon-s3, tomcat

Solution

My personal choice for this problem is to use `iptables` to redirect all traffic from port 80 to the upper port (e.g. 8080) the Tomcat is running on.

/sbin/iptables -A INPUT -i eth0 -p tcp --dport 80 -j ACCEPT
/sbin/iptables -A INPUT -i eth0 -p tcp --dport 8080 -j ACCEPT
/sbin/iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080

Problem

First, i just want to see it is not security group setup in ec2 console. because i can setup the apache, which is by fault 80 port, and be able to visit the apache website through 80 port. but for tomcat it works if i use port 8080(by default) or some values bigger than 1023(i think this port). but when i change server.xml(changing 8080 to 80) it cannot work if i use 80 port, i start the service successfully, but there is no 80/http listening. I know it should be some privileges issues(only the root can start service below 1023 port). but i did not know how to do it.

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