Problem

After following the instructions for Installing Confluence on Linux when using CentOS 7, you may find that Confluence is not accessible, and there are no errors in the logs to suggest why Confluence is not accessible.

Diagnosis

• Is the Confluence service listening on IPv4? Running netstat -a will determine what protocol Confluence is listening on, as well as what port it's listening on.
• Is a system firewall, such as firewalld or iptables running?
  • If so, try stopping those firewalls temporarily to see if they're blocking connection to Confluence
• Can external machines telnet to Confluence on the connection port (8090 by default)?

Cause #1

Confluence may not be listening on an IPv4 address, and instead will be listening on an IPv6 address.

Resolution #1

• Add -Djava.net.preferIPv4Stack=true to your JVM Parameters. See Configuring System Properties; and restart Confluence for the changes to take effect

Cause #2

Connections to Confluence may be blocked by firewalld, which is included in CentOS 7 by default.

Resolution #2

• Configure your firewall software to permit connections to Confluence on the port(s) defined in server.xml. Consult your firewall documentation for details.