Sometimes there is a great article, some useful information or anything else on a web site you want to preserve. When downloading the page in the browser by using something like Save as ... this doesn’t work properly all the time. But don’t worry, there is a solution for this.
Continue reading
Nowadays many govermental authorities or network administrators think that blocking all the network traffic for security reasons is a good idea. One common approach is to block everything, but allow some traffic that is whitelisted. Thus it is not possible to do all the interesting stuff that the firewall prevents to do. But by blocking http or https no webserver would be available any more. So normally these ports are open and thus this is the way to go. Continue reading
When developing software, sometime it’s necessary to sniff the traffic that is transmitted between two computer systems. For that purpose tools like wireshark or tcpdump may be useful. Wireshark is a great tool, but when handling encrypted connections it is not possible to decrypt the traffic without having the key used for encryption. When sniffing http traffic the private key of the certificate is required to decrypt the information. But when talking to a foreign server, without having its private key another approach is necessary. Continue reading
When using swap the system is going to be dramatic slow and maybe hangs for seconds as the performance of the next level memory is dramatically slower then random access memory. In case there is not enough physical RAM and swapping happens really often, there is a way to compensate this approach a little bit by using compressed in-memory swap space. Continue reading
When doing cryptographic operations on a system generating random numbers is required. But accessing /dev/random might be slow in case there is not enough random input. Let’s have a look how to provide some additional random data to improve the speed of random number generation. Continue reading
When running Debian Linux with VirtualBox there is limited support for high display resolutions. Per default a maximum resolution of 1024x768 is possible. For a modern operating system this resolution is definately not state of the art.
But there is a way to support a higher resolution than 1024x768. It is possible to switch to a resolution like 1920x1080 or more. Even more than one display is possible. Continue reading
Currently using legal video streaming is a quite tough topic. As drm mechanism prevent most of the users to use legal video streaming on Linux. I don’t want to make some advertisement, but using Amazon Prime/Instant Video, Google Play, Netflix etc.. is not working out of the box. But Netflix provided a way to use Google Chrome for streaming. Continue reading
As default in many Linux distributions root login via ssh is possible. But depending on your risk awareness this might be a bad idea. E.g. normally you should not work as root, but have a special user that adminsters the system. So why allowing to login as root via ssh? For that reason it’s a good idea to deactivate the possibility to login as root. Continue reading
Sometimes it is necessary to ensure the system clock of all systems is synchronized. E.g. when running a virtual machine, depending on your virtualization technology and your settings your system clock may diverge. This can be achieved by updating the system clock using ntpd regularly. Continue reading
Normally for each device, service and software there should be used a unique password. As this isn’t an easy tasks, many people use a default password for a number of services and devices. But using Linux there is a small smart tool that generates passwords easily. This tool is called apg. Furthermore storing all the passwords in a safe enhances comfort and security dramatically.
Continue reading