SELinux (Security-Enhanced Linux) is a security module that is delivered with the operating system. The default setting for this feature is set to the highest level (strictest) of security. A number of i2b2 users have encountered various connection issues when this feature is turned on. Therefore, in order to avoid issues with your i2b2 installation, we recommend you disable The recommended fix is to enable remote network connections in httpd. Another option (not recommended) is to disable the SELinux feature. More information can be found in the i2b2 Usage Community FAQ.