Several sources provide IP blacklist free to download, you can leverage the blacklist to plan the blocking policies for your own firewall.http://myip.ms/files/blacklist/csf/latest_blacklist.txthttp://infiltrated.net/blacklistedAssuming that we have… Read More »How to Maintain Blacklist for IPTables Atomatically
Here I demonstrate how to remove files with names containing special characters: $ echo "Hello" > "177" $ ls -il total 2 234981… Read More »How to Remove Files with Names Containing Special Characters
As I can remember, command cp never asks you the copy operation for sure except that you add -i option to enter the interactive mode. But with… Read More »How to Copy Files Without Prompts on Enterprise Linux 6
When PHP mail() sent out a message to an external mailbox, the message appeared that the return-path and sender address was email@example.com. Let's see an… Read More »How to Rewrite Return-Path and Sender Address in Postfix
To force an online or dead user to logout, you can use skill to terminate her/his session. For example, I am a root and at… Read More »How to Force Users to Terminate, Exit or Logout
There are several ways to know who are still logged in and where (IP Address) they come from on your Linux server.Command "w"[root@test ~]# w 06:01:53… Read More »Who Are Still Logged in? and Where Are They From?
Swappiness is a value from 0 to 100 which determines the degree of utilizing swap (the virtual memory). A value of 100 means that the… Read More »What is Swappiness and How to Change it?
After modifying the iptables manually, restarting the service to make it work.[root@test ~]# vi /etc/sysconfig/iptables[root@test ~]# service iptables restartiptables: Setting chains to policy ACCEPT: filter… Read More »How to Persist Manually Modified Iptables Across System Reboots
Openssl announced a vulnerability (CVE-2014-0160) in the handling of the TLS heartbeat extension on April 7th, 2014. Version 1.0.1 before 1.0.1g and 1.0.2 before 1.0.2… Read More »How to Update Openssl to a Fixed Release against HeartBleed on Enterprise Linux 6.4
There's only 512MB physical memory and no swap on the server:[root@test ~]# free total used … Read More »How to Enable a Swap File on CentOS 6.5