To use curl to test basic network connectivity, you need to know several things:
- The remote server name or IP address.
- The protocol for the service to be tested (HTTP, FTP, SMTP, etc.)
- The port number for the network application you want to test.
To open a connection to a remote server, open a terminal window on your computer, and then type curl protocol://IP/host:port, where protocol is the communication protocol to be used IP/host represents the IP address or hostname of the server, and port represents the TCP port number. Port is optional when the standard port for a given protocol is used.
C:\>curl http://asgaur.com <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>301 Moved Permanently</title> </head><body> <h1>Moved Permanently</h1> <p>The document has moved <a href="http://asgaur.com/wp/">here</a>.</p> </body></html>
Use curl to try and connect via SMTP protocol
C:\>curl smtp://asgaur.com C:\>curl smtp://asgaur.com:2525 (2525 custom port if any) 214-Commands supported: 214 AUTH STARTTLS HELO EHLO MAIL RCPT DATA BDAT NOOP QUIT RSET HELP
To test an FTP server, use curl to connect via ftp protocol or to port 21.
C:\>curl ftp://asgaur.com C:\>curl asgaur.com:21 220---------- Welcome to Pure-FTPd [privsep] [TLS] ---------- 220-You are user number 18 of 50 allowed. 220-Local time is now 10:04. Server port: 21. 220-This is a private system - No anonymous login 220-IPv6 connections are also welcome on this server. 220 You will be disconnected after 15 minutes of inactivity.
SSH uses encrypted connections. However, you can still use curl to verify that the service is running on a server.
C:\>curl asgaur.com:22 SSH-2.0-OpenSSH_XX