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

问题:

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.

回答1:

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

回答2:

The way I did this previously was to use Apache2 as a proxy using virtual hosts, and proxy onto Tomcat. this will handle the requests and then can also be used as a load balancer if in the future you decide to use multiple Tomcats for load balancing.

回答3:

A common way to configure Tomcat to run on a privileged port on Linux is to use authbind.

Below are the setup steps for Tomcat 7 on Ubuntu 16.04.

First make sure authbind is installed:

sudo apt-get install authbind

Edit /etc/default/tomcat7 and uncomment this line:

AUTHBIND=yes

Create bind permission files for port 80:

sudo touch /etc/authbind/byport/80
sudo chmod 500 /etc/authbind/byport/80
sudo chown tomcat7 /etc/authbind/byport/80

If you are also using https, do the same as above for port 443.