Centos 7 “Single-User” Mode

Yup, for when you’ve forgotten the root password! Rather than copy/paste the details I’ll just link to a couple of reference sources. (Cheers Darren!) Boot in single user mode on CentOS 7 / RHEL 7 Single User Mode in CentOS 7 / RHEL 7

Postfix Rate Limiting

Following on from the excellent advice here: https://www.e-rave.nl/rate-limit-incoming-mail-on-postfix and here: http://steam.io/2013/04/01/postfix-rate-limiting/ You may want to add the following: smtpd_client_event_limit_exceptions = Without it postfix defaults to smtpd_client_event_limit_exceptions = $mynetworks and won’t apply rate rules to hosts within those networks. So if your problem is internal servers hammering your relay then the limits won’t get applied. Oh, … [Read more…]

OVH vRack With Public IPs and Citrix XenServer

If you install XenServer on a dedicated server from www.ovh.ie it comes with two NICs defined. NIC1 is the “normal” bridge network that has the server public/management IP address. IF you want to add “normal” IPs that you’ve purchased then the normal OVH guides are very good. However, it’s not particularly clear how to add … [Read more…]

Forcing a specific video mode, Centos 7

At the grub prompt, edit the line for the specific kernel and at the end of the line add: video=800×600-24 for 800 x 600 resolution with 24 bit colour. To make this permanent: Edit /etc/default/grub and add the video= to the end of GRUB_CMDLINE_LINUX line. # grub2-mkconfig -o /boot/grub2/grub.cfg This will force the video mode … [Read more…]

Disable SELinux on CentOS 6

To disable SELinux on CentOS 6, edit the following config file: # nano /etc/selinux/config Change SELINUX=enforcing # This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing – SELinux security policy is enforced. # permissive – SELinux prints warnings instead of enforcing. # disabled … [Read more…]