Howtos / Articles

Enable IP Forwarding on Ubuntu 13.04

This howto guide outlines the steps to enable IP forwarding on Ubuntu 13.04. This is required if you want your system to act as a router. Check the current setting: $ sysctl net.ipv4.ip_forward This should output a 0 or a 1 depending on if it is already enabled or not. eg: the following shows where ip forwarding is disabled $ sysctl net.ipv4.ip_forward net.ipv4.ip_forward = 0 Enable the kernel option for IP forwarding: $ sudo sysctl net.ipv4.ip_forward=1 eg: $ sudo sysctl…

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How To Disable IPv6 on CentOS

A default install of CentOS will enable IPv6 connectivity. If you don’t need IPv6, there is no need to have it enabled. Follow the steps below to disable IPv6 on a CentOS install. Note: Run these commands as a user with root privileges. Check to see if you’re installation is currently set up for IPv6: # cat /proc/sys/net/ipv6/conf/all/disable_ipv6 If the output is 0, IPv6 is enabled.
If the output is 1, IPv6 is already disabled. Edit the /etc/sysctl.conf file to…

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How To Disable IPv6 on Ubuntu

A default install of Ubuntu will enable IPv6 connectivity. If you don’t need IPv6, there is no need to have it enabled. Follow the steps below to disable IPv6 on a Ubuntu install. Check to see if you’re installation is currently set up for IPv6: $ cat /proc/sys/net/ipv6/conf/all/disable_ipv6 If the output is 0, IPv6 is enabled.
If the output is 1, IPv6 is already disabled. Edit the /etc/sysctl.conf file to set the kernel parameter to disable IPv6: $ sudo nano…

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Disable icmp ping replies on Linux

Having a computer that replies to ping requests allows for simple network connectivity tests, however there may be circumstances where you need to disable ping replies coming from your computer. This can be done using firewall rules, however Linux provides an easy way to change the kernel parameters at run time to disable ping replies. Kernel parameters can be changed using the ‘sysctl’ command. Command to disable ping replies: $ sudo sysctl -w net.ipv4.icmp_echo_ignore_all=1 Command to enable ping replies: $…

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