Contents
Does Curl support TCP?
Most of the protocols you use with curl speak TCP. With TCP, a client such as curl must first figure out the IP address(es) of the host you want to communicate with, then connect to it. “Connecting to it” means performing a TCP protocol handshake.
What TCP port does curl use?
IMAP servers and clients use TCP port 143. Whilst connections to the server start out as cleartext, SSL/TLS communication may be supported by the client explicitly requesting to upgrade the connection using the STARTTLS command.
Can you use curl to test a TCP connection?
Say, you’re helping with some firewall changes and need to confirm that connection from your server to some remote host and specific TCP port still works. Here’s how you can do it using curl command and its telnet functionality.
How can I run multiple curl requests processed sequentially?
So the simplest and most efficient (curl will send them all down a single TCP connection [those to the same origin]) approach would be put them all on a single invocation of curl e.g.: Another crucial method not mentioned here is using the same TCP connection for multiple HTTP requests, and exactly one curl command for this.
What can I use curl command to test?
But there’s another great usage curl command has: testing TCP ports connectivity. Say, you’re helping with some firewall changes and need to confirm that connection from your server to some remote host and specific TCP port still works. Here’s how you can do it using curl command and its telnet functionality.
How can I limit the number of parallel TCP connections?
This just accepts futher packets belonging to accepted connections. Also –syn tells it to pay attention to (or count) the packets that set up a TCP connection. You need to use the connlimit modules which allows you to restrict the number of parallel TCP connections to a server per client IP address (or address block).