Category Archives: Linux

Stuff about Linux

Linux: Move a process from fore- to background

July 23, 2015 Michael Albert Leave a comment

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Hi,

bash offers the ability to move a running foreground process into background.

An example Listen with netcat at tcp port 80, this process to not exit and stays in foreground.
root@debdev:~# nc -l -t -p 80 -s 10.254.1.1
Now I want to do some other things in this console.
Continue reading Linux: Move a process from fore- to background →

Linux

DNS: Configure DNS to return the same IP Address for all hostnames

July 22, 2015 Michael Albert 1 Comment

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Hi,

its possible to catch all DNS host queries to just one IP Address. For example in an open WLAN to redirect a User to a authentication page before he can use the network.

Continue reading DNS: Configure DNS to return the same IP Address for all hostnames →

Linux, Raspberry PI

Linux: Configure a tiny DHCP Server

July 22, 2015 Michael Albert 1 Comment

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Hi,

the best choice to setup a very tiny dhcp server on linux is the busybox udhcpd DHCP implemention.

root@debdev:~# apt-get install udhcpd
Continue reading Linux: Configure a tiny DHCP Server →

Linux

Linux: Regenerate sshd host keys

April 22, 2015 Michael Albert 5 Comments

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Hi,

to generate sshd host keys, for example in case of cloning a virtual linux instance, do the following steps:

Checkout the key file names
root@debdevt:~# grep HostKey /etc/ssh/sshd_config # HostKeys for protocol version 2 HostKey /etc/ssh/ssh_host_rsa_key HostKey /etc/ssh/ssh_host_dsa_key HostKey /etc/ssh/ssh_host_ecdsa_key HostKey /etc/ssh/ssh_host_ed25519_key
Continue reading Linux: Regenerate sshd host keys →

Linux, OpenVPN, Security

OpenVPN: Built a certification authority from scratch with openssl

March 18, 2015 Michael Albert 9 Comments

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Hi,

these are the steps to build your own CA (Certification Authority) and all requiered certificates for a OpenVPN instance (Client and Server) on Linux.

Define your environment. Always set these variables in the shell before executing openssl commands. Adjust it to your needs.
Continue reading OpenVPN: Built a certification authority from scratch with openssl →

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