SSH login using pair of key with no password

In this paper I will present the easiest way to use key pair for loggin to ssh servers. Everything is done in linux operating system. On client computer we generate our public and private key: course. ssh-keygen -t rsa -b 4096 Now to use our key for logging we have to upload it to the […]

Gmail ipv6 no PTR record rejected emails.

If You get the following message on the ISPconfig server running postfix: „Our system has detected that this message does 550-5.7.1 not meet IPv6 sending guidelines regarding PTR records” Then i suggest following work-around: Go to /etc/postfix/master.cf find line: smtp unix – – – – – smtp and change it to: smtp unix – – […]

Howto copy linux os to new hard drive with GPT partition table.

This method was tested on linux lubuntu. All debian like system schould do the same. Use gparted to create partitions on new hard drive. Remember to create first partition 100 MB in size fat32 (vfat) as type, and set boot flag to it! We assume that You have connected new hard drive to your working […]

Howto make power led not blinking in sleep mode.

Hi, recently I have bought asrock H97 chipset motherboard. What is strange for me manufacturer has changed default power led behaviour. I have good night led option: enabled/auto – power led is off – equal to unplugging led disabled – power led is on when pc is on, led is blinking when in sleep mode […]

Windows 7 boot problems fix

Hi, recently after installing Linux or resizing partition using Gparted I came up with a boot problem of my windows instance. Solution is to boot from installation dvd. Then you have to choose language and go for repair console. Once it is open you can try these set of commands: bootrec.exe /FixMbr bootrec.exe /FixBoot bootrec.exe […]

Howto autostart and shutdown virtualbox machines gracefully with host shutdown – Lubuntu

Hi, recently I have encountered problem how to shutdown virtual machines when host machine I shutting down. There are many script solutions out there, but the simplest is to use Lubuntu virtualbox package. Then in /etc/default/virtualbox You have to add these to lines at the bottom of the file: SHUTDOWN_USERS=”user names separated by space” SHUTDOWN=”savestate” […]

High performance Linux router with optional LMS web panel and radius server in 5 minutes.

High performance Linux router with optional LMS web panel and radius server in 5 minutes. Every network administrator managing a pool of many routers, knows how important configuration repeatability is. For this reason I have presented how to install high performance router under Debian Linux OS with configuration done in an easily editable text files […]

How to change/delete cache or hibernation partition under diskpart Windows 7.

Recently I wanted to change my hibernation partition size, so I had to delete it and create new one with new size. I have encountered silly problem with deleting hibernate partition. The solution is as follows: 1. Start command line (cmd) as Administrator user. 2. Enter diskpart <enter> to partition manager. 3. list disk <enter> […]

Lenovo Thinkpad W530 – 30 day sleep howto.

I was curious how  the 30 day sleep (S4) feature works. In normal sleep mode(S3) my Lenovo Thinkpad W530 overnight takes around 10% from 9 cell battery.   First of all you will need to have hibernation partition which size is not necessary equal to your RAM memory size. Not many people know that if […]

Windows 7 low disk space warning.

Recently I have come across an annoying problem. If you have a big HDD, for example 1TB, windows will issue a  red warning bar on your computer when you have still around 100GB of free disk space. For me seeing something red means that disk is failing, it draws my attention for no reason. For […]