SetServer command actually returns an error if given an invalid server

client/client.go

@@ -602,6 +602,16 @@ func (c *Client) SetServers(in []string) error {
 			continue
 		}
 
+		// Try to ping to check if it is a real server
+		ok, err := c.Ping(addr)
+		if err != nil {
+			merr.Errors = append(merr.Errors, fmt.Errorf("Server at address %s failed ping: %v", addr, err))
+			continue
+		} else if !ok {
+			merr.Errors = append(merr.Errors, fmt.Errorf("Server at address %s didn't respond to ping", addr))
+			continue
+		}
+
 		endpoints = append(endpoints, &servers.Server{Addr: addr})
 	}