Cornucopia of Ideas GNU/Linux, Networking, Security and more ...

Screen & Rsync

Screen: Default key binding Ctrl+a d: Detach screen from this terminal. Ctrl+a r: Reattach a session and if necessary detach it first. screen -ls : Lists existing screen sessions. scren -r : To reattach existing session to foreground. gns3@gns3:~$ screen -ls There is a screen on: 4485.pts-5.gns3 (07/16/2017 06:39:04 PM) (Attached) 1 Socket in /var/run/screen/S-gns3. screen -r <session id> gns3@gns3:~$screen -r 4485 Rsync: To send a file with rsync over ssh protocol(ssh key); You can apply below command.

Connect to Real World With GNS3

GNS3 is a GPL licenced cross-platform network simulation program. It enables us both virtual and physical networks operate together. It emulates Cisco IOS, doing so we have real Cisco device capability in a Virtual Machine. You can also analyze the packets with Wireshark. One exception that GNS3 has limited device capability as some Cisco devices impossible or very difficult to simulate them. Also some devices need real hardware to operate. For supported Cisco devices and FAQ, Link.

Port Forwarding on Windows 10

Hi Folks! Port Forwarding is a way of making computer, in which located private LAN, accessible on the Internet. Even though it is behind the router. It is used for gaming, surveillance IP cameras, accessing your personnel computer on the Internet. Actually, in this post port forwarding is used for accessing a web page that runs on CentOS7 virtual machine, which is hosted on Windows 10. You can catch a glimpse of picture for better understanding in Figure 1.

SSL Validation and Troubleshooting

There may be times when we have a problem with SSL certificate because of some issues such a missing intermediate certificate, self-sign certificate and etc,. It may be exhausting to figure out what exactly the problem is. Even though, web browsers give some details about problem, It is not enough to solve the problem sometimes. Actually some tools has existed battling with this problem. In this post I will give you an information about the tools.

Encrypting with aespipe

Hi folks! It has been long time that I did not post anything on my blog. Actually, I set sail for new adventure, new job– I will move to Wrocław, Poland. So I have many things to do. Anyway. In this post, I write about encrypting a file in Linux. Actually, there are many command line tools for this. In this post I will write about aespipe. Aespipe is a command line tool that can be used to create and restore tar or cpio archives.


Hi Folks! Introduction: In this post, I will introduce you about packer. Packer is actually open source tool for creating machine and container images for multiple platforms from single source of configuration. As a configuration It uses a json syntax for creating machines for different platforms such as Amazon EC2, Docker, VirtualBox, VMware etc. Actually I will not get into more detail. For more information please visit website. As an example, I created very simple configuration for VMware Workstation platform by installing CentOS 7 without keyboard interaction.