At times, in systems configured to use both IPv4 and IPv6 addresses the debian package manager (apt / apt-get / aptitude) uses IPv6 by default for outgoing connections and fails to resolve/connect. The solution is to force it to use IPv4

Add -o Acquire::ForceIPv4=true when running apt-get or apt.

If you want to make the setting persistent just create /etc/apt/apt.conf.d/99force-ipv4 and put Acquire::ForceIPv4 "true"; in it:

echo 'Acquire::ForceIPv4 "true";' | sudo tee /etc/apt/apt.conf.d/99force-ipv4

Kerala Gramin Bank popularly known as KGB, based out of Kerala has banking application for Android phones, but there also exists a web interface, which is not widely publicized. Couldn’t find the link anywhere in the website or even with a google search.

The URL is https://mobile.canararrb.com/kgbmpaywap/kgb

It uses OTP to registered mobile number for authentication, along with a registered PIN.

It does most of the basic functions including balance check, mini statement, NEFT and IMPS based transfers. Really helpful for those who hate to use mobile applications due to various reasons.

Having a gigabit connection and choosing a far-away mirror causing long time to update system is always frustrating. Its also hard to figure out the nearest mirror for every server, when you are dealing with servers deployed world-wide.

Luckily for Debian, there is a mirror selector which automatically finds the nearest one and uses it while working with apt.

To use it, replace the currently configured Debian mirror in sources.list with the following address:

http://httpredir.debian.org/debian

e.g. for Debian jessie

deb http://httpredir.debian.org/debian jessie main contrib non-free

Its also available for Backports and older versions. More details at http://http.debian.net/

Script 1:

wget freevps.us/downloads/bench.sh -O - -o /dev/null | bash

Script 2: (Credits)

wget dl.getipaddr.net/speedtest.sh 2>/dev/null -O- | bash

Fail2Ban is an intrusion prevention framework written in the Python. It ban IP’s that makes too many failed attempts or performs any other unwanted action within a time frame defined, using iptables, thus helping the system admin to prevent attacks.

Though its very helpful, in an office network that has only one public IP and multiple users accessing the same server, there are chances that IP’s gets blocked more frequently. For Eg, let the setting be like 3 failed attempts on ssh port in 60 mins will block the IP for 2 hours. If 5 systems in a network access the server and any 3 of them makes one failed attempt, the IP gets blocked.