https://prod.jnet.julianscorner.com/ 2026-04-17T12:21:25+00:00 https://prod.jnet.julianscorner.com/ https://prod.jnet.julianscorner.com/_media/wiki/dokuwiki-128.png text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/autofs_smb Configure System To Automount a Samba Share First, make sure that the CIFS mount tool is installed: sudo apt-get install cifs-utils Next, edit the /etc/fstab file and put an entry for each Windows/Samba share that you want to mount. //server/share /mnt/share cifs credentials=/root/.smbpasswd,file_mode=0666,dir_mode=0777 0 0 | | | | | | | ^--------- Mount Options | | ^-------------- Type of file system (smbfs or cifs… text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/cluster_config Updating Cluster Configuration Any time you need to update the cluster configuration, you must tell the other nodes that the file has changed. First, backup the /etc/cluster/cluster.conf file. Edit /etc/cluster/cluster.conf and make the changes. Tell The cluster system that the configuration file has changed: text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/customize_shell Customize Linux Shell These are the steps I do the first time I log on to a Linux system. cat >> ~/.bashrc << EOF case \${TERM} in dumb) # Filezilla doesn't like my profile ;; *) ################################################################ # Julian's Aliases alias dir='ls -lah' alias ll='ls -lh --color=auto' alias ls='ls --color=auto' alias cls='clear' alias df='df -h' alias du='du -h' alias grep='grep --color' alias diskusage='du -h --m… text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/emergency_reboot Emergency Reboot or Shutdown on Linux Most linux distributions use some type of mechanism to gracefully stop daemons and unmount storage volumes during a reboot or shutdown. It’s most commonly done via init or systemd scripts that will wait for each daemon to shut down gracefully before proceeding to the next script. text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/hyperv_guest Configure Linux Kernel on Hyper-V Hosted VMs Ubuntu (since 12.04) is supported as a guest virtual machine in Hyper-V. I used to run a separate KVM host server to run Linux VMs, but since Ubuntu (as well as CentOS since 6.4) can run under Hyper-V, I've switched to running just Hyper-V on the host. After the initial install of the text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/ipv6_aptget Force Apt-Get to Not Use IPv6 I've implemented IPv6 on my home network and noticed that several of my Ubuntu machines have trouble updating via apt-get when it tries to reach out to the update servers via their IPv6 address, especially the security.ubuntu.org text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/ipv6_disable Disable IPv6 Protocol Current Linux Kernels I recently had to disable IPv6 on one of my Linux VMs (running Xubuntu 15.04) and realized that the method to disable IPv6 in recent kernels had changed. The current way is to edit the file /etc/sysctl.conf text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/ipv6_privacy IPv6 Privacy Extensions Privacy Extensions as defined in RFC4941 make your device change its IP every now and then. In Ubuntu, these privacy addresses are not enabled by default. Their generation is activated via the sysctl directive use_tempaddr that can be set to one of the following values: text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/lvm Logical Volume Manager (LVM) Management Logical Volume Manager (LVM) is used in Linux to abstract the filesystems away from the physical disk they sit on. Mounting Volume Groups Volumes can be grown online BUT cannot be reduced online. In order to reduce a volume group, the volume must be unmounted. For volumes containing the root file system, you need to boot using a live boot CD. Once the live CD is loaded, you can activate the Volume Groups by typing: text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/nic_bonding Network Card Bonding Bonding is the ability to combined network interfaces as one. Bonding allows you to aggregate multiple ports into a single group, effectively combining the bandwidth into a single connection. Bonding also allows you to create multi-gigabit pipes to transport traffic through the highest traffic areas of your network. For example, you can aggregate three megabits ports into a three-megabits trunk port. That is equivalent with having one interface with three megabytes speed. text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/openssl SSL Certificate Management Generate Certificate Request Most CAs will require a person to submit a certificate signing request (CSR)... With Chrome v58, the developers removed support for Common Name checking so you need to generate certificate request including the SAN (Subject Alternative Name) field to be accepted by Chrome browser. text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/ssh_host_keys Avoid Duplicate SSH Host Keys It was recently discovered that a cloud hosting company mistakenly add SSH Host Keys to their image. Best practices state that these host keys should be unique for each host. If host keys are reused, there is no way to prevent someone else or a different system with the same key from impersonating the host and potentially performing a Man-In-The-Middle attack. I also like to regenerate the host keys whenever I use a template or have to provide text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/staticnetwork How to set a Static IP in Ubuntu Prior to 17.10 First, we need to shutdown the interface: sudo ifdown eth0 To specify a static connection we need to change the Ethernet's interface configuration in /etc/network/interfaces: iface eth0 inet static address 192.168.0.101 gateway 192.168.0.254 netmask 255.255.255.0 dns-nameservers 8.8.8.8 8.8.4.4 text/html 2023-09-18T20:00:11+00:00 Anonymous (anonymous@undisclosed.example.com) https://prod.jnet.julianscorner.com/linux/systemdjournal Clear SystemD Journal On any server, the logs can start to add up and take considerable amount of disk space. Systemd conveniently stores these in /var/log/journal and has a systemctl command to help clear them. Clear systemd journals older than X days