Quick TIP: Postfix Reverse lookup
When your maillog on a CentOS/*EL machine looks like this: mail postfix/smtpd[19345]: connect from unknown[XXX.YYY.ZZZ.QQQ]
Tag: CentOS
Hosting a Virtual Machine With a Public IP (proxy_arp)
I run this website on a physical server that i rent. Recently I wanted to run on the same server a virtual machine, with a different OS, with a public IP address(I use KVM for that, as there’s nothing to really change on the physical server’s OS and performance-wise it’s…
Removing old kernels
On Debian/Ubuntu we would need to search for installed kernel packages, something like this: root@server:~# dpkg --list |grep linux-image ii linux-image-3.2.0-23-generic 3.2.0-23.36 Linux kernel image for version 3.2.0 on 64 bit x86 SMP ii linux-image-3.2.0-56-generic 3.2.0-56.86 Linux kernel image for version 3.2.0 on 64 bit x86 SMP ii linux-image-3.2.0-57-generic 3.2.0-57.87 …
RHEL (CentOS) – changing Apache’s MPMs
Well, in EL6 when we wanted to change Apache’s MPMs we would edit /etc/sysconfig/httpd and set the HTTPD variable with the binary needed.It looks something like: HTTPD=/usr/sbin/httpd.worker To see the available options we could type the following command: [root@server ~]# ls /usr/sbin/httpd* /usr/sbin/httpd /usr/sbin/httpd.event /usr/sbin/httpd.worker The simple httpd binary uses…
Centos7 – reversing to classic iptables
First of all we need to deactivate FirewallD systemctl disable firewalld.service Then we install the package called iptables-services yum install iptables-services edit /etc/sysconfig/iptables then start classic iptables and make it load on each reboot systemctl start iptables.service systemctl enable iptables
Testing CentOS 7 – Lots have changed
So, just installed the newly launched CentOS 7 and oh boy! Lot’s have changed.Honestly I don’t know if it’s for the good or bad. As I observed the distro moves really fast, and it starts reeeeallly fast! The first notable change is that the default filesystem changed to XFS. Therefore…
RedHat and CentOS
Few days ago a press release announcing “RedHat and CentOS Join Forces to Speed Open Source Innovation” has put some thoughts into some people that started articles called “Hell Freezes Over in Linux Land as Red Hat Makes Nice With Its Clone“. No guys, you got it wrong! First of…