This tool helps you to test REST API /SOAP Web requests very easily. Fiddler acts as Web Proxy and it sits between Client Application and Web Server. Fiddler only starts capturing traffic when you running it. By default, it runs on a local machine (127.0.0.1) Port 8888. You can change the default port from Tools > Fiddler Options. Aug 13, 2018 · The connection to the server localhost:8080 was refused - did you specify the right host or port? [email protected]:~# curl localhost:8080 curl: (7) Failed to connect to localhost port 8080: Connection refused To reproduce, follow the instructions provided on this techrepublic article.