ping request

You can simply monitor your remote system hosted some remote IDC. There may be tons of causes for which system goes out the network. Understanding ping command ping is one of the basic and nifty command to test network connection. For example you can send 4 ping request to with following command: $ ping […]


The Internet Control Message Protocol (ICMP) has many messages that are identified by a “type” field. You need to use 0 and 8 ICMP code types. => Zero (0) is for echo-reply => Eight (8) is for echo-request. To enable ICMP ping incoming client request use following iptables rule (you need to add following rules […]


This is very common scenario. You want to permit access to a remote machine only by SSH. You would like to block all incoming traffic to your system except ssh connection under Linux.