SNMP v3 and Cacti
A quick synopsis on setting up a Cisco ASA and a Centos 6 or 7 system to use SNMP v3 to be monitored by Cacti Cisco ASA en conf t # create a snmp-server group (needed for SNMP v3) # … Continue reading →
Category Archives: Centos 7
How to mount raw images (.img) images on Linux
If you have a few .img files coming as disk images from devices like floppies, CDs, DVDs, SD cards, etc, you will realize that you cannot mount the in Linux, because they contain a file system that has to be … Continue reading →
Change port for sshd server
I changed the port for sshd on my servers to reduce the number of attacks against the sshd server. In the following example, I am changing the port from the default of 22 to 43231 First – backup your sshd_config … Continue reading →
DRBD on Centos
Installation Centos 7 rpm –import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm yum -y install drbd84-utils kmod-drbd84 Centos 6 rpm –import http://elrepo.org/RPM-GPG-KEY-elrepo.org rpm -Uvh http://elrepo.org/elrepo-release-6-5.el6.elrepo.noarch.rpm rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm rpm –import ‘http://keys.gnupg.net:11371/pks/lookup?search=0x0608B895&op=get’ yum -y install drbd84-utils kmod-drbd84 Configuration create /etc/drbd.d/drbd1.res resource repdata { protocol … Continue reading →
Could not apply stored configuration to monitors
You log onto your linux system and you get the message “Could not apply the sotred configuration to monitors” Start a bash prompt cd ~/.config mv monitors.xml monitors.xml.zzz Log off and log back on again
Continue reading →Set Time Zone From ISC DHCP Server
Hand out the time zone from your ISC DHCP Server Add the following lines to the top of your dhcpd.conf file option PCode code 100 = text; option TCode code 101 = text; option PCode “EST5EDT4,M3.2.0/02:00,M11.1.0/02:00”; option TCode “America/NewYork”; … Continue reading →
Disable ipv6 on a single interface or all interfaces
1. Append below lines in /etc/sysctl.conf: net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 NOTE : To disable IPv6 on a single interface replace “all” on the first line with “eth0” or the name of the selected ethernet interface 2. To make … Continue reading →
Some Simple FirewallD Examples
Using Firewall-cmd to check firewall current state If you want to verify the current state of firewall then you need to use –state option with firewall-cmd command to check that. As you can see from below output, firewalld is currently … Continue reading →
RDesktop on Centos
Centos 7 yum -y install epel-release yum -y groupinstall “GNOME Desktop” yum -y install xrdp xorg-x11-xinit firewall-cmd –permanent –zone=public –add-port=3389/tcp firewall-cmd –reload systemctl start xrdp.service systemctl enable xrdp.service Centos 6 rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm wget -O epel6.key.txt ‘http://keys.gnupg.net:11371/pks/lookup?search=0x0608B895&op=get’ rpm –import epel6.key.txt … Continue reading →
Move a virtual machine from one Centos machine to another
Revised: How to migrate a kvm guest from one host to another. These instructions are for moving a guest machine from one host to another host where the storage is on the host (instead of external storage that can be … Continue reading →