Trying to use hping3
I typed the following command: (assume my linode is 198.51.100.123)
hping3 -S -p 443 198.51.100.123
I get the response:
3 packets transmitted, 0 packets received, 100% packet loss
Why do I get this result and how can I fix it? Do I need to solve the problem in my PC or on the server?
Could you kindly provide more information about what you are trying to do and what result you are looking for? You may wish to review the following post which will help you frame your question in a way that will offer the best chance for getting a solution to your problem: https://www.linode.com/community/questions/17096
If you are using a guide that is instructing you to use that command, can you kindly provide the URL to the guide to provide context for your question?
It looks like you are trying to see if your web server is susceptible to a SYN flood denial of service attack or are testing to see if you have connectivity to your site.
I am not sure whether you are running the command from the Linode or from a remote PC. I will assume for the sake of this reply that you are attempting to run the command from your local computer to your Linode.
The result you provide informs you that your server is not responding to SYN packets sent to it on port 443 (https) on your Linode. This could mean that either your web server is not running, a firewall is preventing the packets from reaching your web server, or your web server is not responding to those packets.
If you are testing to see if your web server is running, then you will want to try browsing your page using https://18.104.22.168, or using the command (change the IP address to match your own):
curl -I https://22.214.171.124
To see how latency varies from request to request over time you can use something like the following from a Linux computer:
watch time curl -I https://126.96.36.199
If you are trying to see how your web server performs during a SYN flood, then you may wish to use the out of band console on your Linode and monitor the 'top' command from your LISH Console This will allow you to monitor performance of your resources, such as processor or memory usage even if the network is affected. You want to use the --count flag with the hping3 command and slowly increase the number of packets from 3 upward until you can detect a slight performance decrease. You do not want to increase the count above this point, or black helicopters may start hovering over your house.
If you are checking your firewall rules you may want to refer to this post which explains iptables accounting:
If you are trying to do something else, please let us know.
I hope this is helpful.