I have a server A which is configured behind a firewall and has 30.x.x.x public adress and 172.x.x.x internal address. I'm trying to make a php Curl call from a script located on that server, to the 30.x.x.x external IP of that server but the curl call cannot be resolved. It seems that server A does not have a route to that IP. Did you encounter any similar situations? Any chance to solve it through static routes?