To verify if IPv6 is enabled or not, execute : # ifconfig -a | grep inet6 inet6 fe80::211:aff:fe6a:9de4 prefixlen 64 scopeid 0x20 inet6 ::1 prefixlen 128 scopeid 0x10[host] 1. Disable IPv6 in kernel module (requires reboot) 1. Edit /etc/default/grub and add ipv6.disable=1 in line GRUB_CMDLINE_LINUX, e.g.: # cat /etc/default/grub GRUB_TIMEOUT=5 GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT=”console” GRUB_CMDLINE_LINUX=”ipv6.disable=1 crashkernel=auto… Read More »

To change the default SSH port, the first thing you want to do is backup the current SSH configuration on your system. To do that, run the commands below. cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak Next, run the commands below to open the default SSH configuration file sudo vi /etc/ssh/sshd_config # If you want to change the port… Read More »