Howtos / Articles

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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Display process name and ID of network connections

The netstat command on Linux shows you any active and listening network connections on the computer. If there is a connection active that you are not sure what it is, you can use the ‘-p’ (or ‘–programs’) parameter to show the process id (PID) and process name of the network connection/socket. Example: Note: to use the -p parameter, you need to have root privileges, otherwise the ‘PID/Program name’ field will just display ‘-’.…

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Reload HAProxy Config with Minimal Downtime

Restarting HAProxy using the default init scripts will kill any existing connections, and prevent any new connections while it restarts. With the init script restart method (eg ‘/etc/init.d/haproxy restart’), if there are any configuration errors, the service wont start up again. This might be fine for low volume sites, but if you are dealing with heavy traffic, you would want to reload the configuration with the smallest amount of downtime possible. Thankfully HAProxy provides the ability to do this. The…

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Configure a PPTP VPN Server on Ubuntu Linux

If you need to access your network (be it a home network, or a work network) from a remote location, a great option is to set up some sort of VPN connection. There are a few different types of VPN connections, such as PPTP, L2TP, and IPSec, and each has advantages and disadvantages. One of the advantages of PPTP VPN connections is that almost all devices that can create VPN connections, have a PPTP VPN client already. Linux can be…

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Installing Firebird From Source On Linux

This ‘How To’ article outlines the steps required to compile and install the Firebird database server on a Linux machine. Download the latest version of the source code from http://www.firebirdsql.org/en/server-packages/ At the time of writing this article, the latest version was 2.5.1.26351-0. Replace the URL below with the latest version, or get the source code package onto the Linux machine with some other method. $ wget “http://internode.dl.sourceforge.net/project/firebird/firebird/2.5.1-Release/Firebird-2.5.1.26351-0.tar.bz2″ Extract the downloaded package. $ tar xjvf Firebird-2.5.1.26351-0.tar.bz2 The file list will flow…

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