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showing posts tagged with 'linux'

by lunarg on September 19th 2016, at 11:59
If you get a keyserver time out when trying to download a public key from a public GPG server, you may need to check your firewall settings. When receiving a public key, gpg connects to TCP port 11371, which not commonly opened up when you are behind a strict firewall. Luckily, most key servers also listen on port 80, allowing to get the public keys through that port.

When attempting to download a key and you are not able to connect to the default port, you will get something like:

gpg --keyserver keyserver.ubuntu.com --recv-keys 94558F59gpg: requesting key 94558F59 from hkp server keyserver.ubuntu.comgpg: keyserver timed outgpg: keyserver receive failed: keyserver error

To force gpg to d  ...

by lunarg on May 27th 2016, at 14:14

https://wiki.gentoo.org/wiki/Safe_CFLAGS

Note: this original post was from May 2007 but someone pointed out to me that the link no longer worked, in an attempt to sell me some web hosting... So... Thanks, but I'm sticking with my current hosting company.

by lunarg on January 18th 2016, at 15:10
Installing the Open Monitor Distribution (OMD) is actually pretty straight forward on Debian. Consol Labs provides a OMD repository from which the latest version of OMD can be installed, providing both a stable and testing branch.

First and foremost, you need to have a Debian/Ubuntu system running, and it needs to be connected to the internet.

In order to add the repository, you need to import the GPG security key in order to trust the repository:

gpg --keyserver keys.gnupg.net --recv-keys F8C1CA08A57B9ED7gpg --armor --export F8C1CA08A57B9ED7 | apt-key add -

Next, add the repository to your sources.list. For Debian 8.0 "Jessie", this would be something like this:

echo 'deb htt  ...

by lunarg on June 24th 2015, at 15:16
For proper troubleshooting of DHCP traffic, it may sometimes be necessary to capture live data on your network. There are a lot of ways on how this is accomplished, so I won't go into too much detail on all the methods available, nor will I explain what DHCP does or how it works.

DHCP (Dynamic Host Configuration Protocol) is used for automatic configuration of a host's network settings, such as IP address, gateway, routing, and more. It works by sending broadcasts using IP/UDP on ports 67 (servers) and 68 (clients). For more information on DHCP, read the explanation on Wikipedia.

In order to capture DHCP traffic, we would then have to monitor packets specifically on port 67/udp and 68/udp.  ...

by lunarg on June 17th 2015, at 10:34
Linux distros with a 3.x kernel running on virtualized hardware (e.g. pvscsi on VMware) may ever so often spit out the following error:

$dmesg | grep "WRITE SAME" kernel: sda2: WRITE SAME failed. Manually zeroing. This is because the disk driver (in our case: the VMware paravirtual driver) does not support the WRITE SAME SCSI command, resulting in this message. While this poses no problem for the system at all, you may want to get rid of these messages, which is done by disabling the use of the WRITE SAME command. This can be done through a bit of configuration. Most modern systems have systemd on board which can be used for this, but in case your system doesn't, there's also a ... by lunarg on June 12th 2015, at 15:55 You can efficiently change the console fonts, character sets and keymaps through the following command: sudo dpkg-reconfigure console-setup The configuration is stored in the file /etc/default/console-setup, and can be edited by hand as well. The changes are effective for all virtual consoles after reboot. To apply the change for the current console, run: setupcon To prevent changing the console font completely (i.e. native system/BIOS font will be used), set the font to "do not change". The equivalent in the config file is: FONTFACE="" FONTSIZE="" by lunarg on June 9th 2015, at 16:18 Nice article about things you can do after a fresh install of Ubuntu on your computer: Very useful if you don't have a whole lot of experience with linux in general, and Ubuntu in particular. by lunarg on June 3rd 2015, at 15:09 SMB (Server Message Block) is an application protocol, most commonly used for file and printer sharing. Although it was originally designed by IBM for use in OS/2, it has been adopted and improved upon by Microsoft as the primary protocol for file and printer sharing in their Windows for Workgroup. It has been in use ever since on Windows and a myriad of other OS flavours. Although SMB is proprietary to Microsoft, SMB is also available on linux (through Samba), Apple (first Samba, then later, Apple's own SMBX), and a myriad of other OS vendors. In fact, Apple has replaced their own AFP in favour of SMB in their latest releases of Mac OSX. SMB has become the most commonly used protocol for f ... by lunarg on May 28th 2015, at 11:17 A nice article about how to set up NIS on Red Hat linux: http://bradthemad.org/tech/notes/redhat_nis_setup.php. by lunarg on May 20th 2015, at 11:18 This is a Perl script I wrote and used for the migration of a linux DHCP server (running dhcpd to a Windows DHCP server. The script looks in the dhcpd.conf configuration file for fixed reservations and exports these to a CSV for processing and importing in another server. Usage is simple, as it takes its input from STDIN and outputs to STDOUT. cat /etc/dhcpd.conf | perl export-dhcpd-reservations.pl > output.csv The script is very simple and can probably do with a lot of improvements, but it's a start for anyone willing to develop it further. It is licensed as GPLv3. by lunarg on May 5th 2015, at 13:05 By default, Kodi (formerly known as XBMC), stores its data directory in the user's home folder (Mac/Linux) or roaming profile (Windows). Sometimes, this may not be desirable, especially when you have only a limited amount of space available on that particular drive (such as having a Windows installation on an small SSD). In that case, you may want to move the entire data directory (including the profiles, thumbnail caches and database files) to another drive. There are various ways to achieve this, but I found out the most easiest (and also complete way) is to simply move the entire folder to another partition or disk, then symlink that folder to its original location. That way, you won't h ... by lunarg on April 21st 2015, at 09:30 To block traffic from/to a specific IPv4 address using iptables, you can use these commands: iptables -A INPUT -s 1.2.3.4 -j DROP iptables -A OUTPUT -d 1.2.3.4 -j DROP Warning! Do not use these commands when you are already running an iptables-based firewall as this may result in unexpected results. by lunarg on June 18th 2014, at 11:53 The quick and dirty way to set up an NTP server on Debian Linux for your network. This has been tested using Debian 7.0 "Wheezy". 1. Install NTP server: apt-get install ntp 2. Edit /etc/ntp.conf: add the networks that are allowed to sync with your time server like so (Adjust parameters accordingly.): restrict 192.168.0.0 mask 255.255.255.0 nomodify notrap 3. Restart the NTP service: /etc/init.d/ntp restart 4. Set your device/computer/server to use your NTP server by lunarg on September 30th 2013, at 09:51 You can change/set the From-addresses in FreePBX to something you want. Change the address in Admin » System Admin. To the right, click on Notification Settings, then fill in the From Address. These are set up from within Asterisk, and are located at Settings » Voicemail Admin. Click on the Settings link, then scroll down until you find serveremail. Change it to whatever you want. Next, because it uses Postfix to e-mail out voicemail notifications, you'll also have to change a parameter in there: Open a shell to your box (SSH). Type nano /etc/postfix/main.cf. Find and change, or add a line: mydomain your-domain-name.com. Fill in the domain you want. It should be the same as ... by lunarg on April 15th 2013, at 08:40 You can script password changes in linux by using passwd without any additional effort. The syntax for this is: echo "your-password" | passwd --stdin user by lunarg on March 28th 2013, at 14:15 You can change the delimiter of a for-loop by changing the value of the global variable$IFS. By default this is set to a space.

For example, if you want the delimiter to be a new line, set it like so:

IFS=\$'n'
by lunarg on March 13th 2013, at 11:13

Simple Linux Load is a simple disk and CPU load generator to stress linux servers. I mashed this up when I had to put some load on a machine to troubleshoot issues with it which were only occuring under load.

It consists of two very simple shell scripts, each generating and deleting a 4GB file, and this in a loop.

• rnd.sh: the file is filled with random numbers, and stresses the CPU more than the disk;
• zero.sh: the file is filled with zeroes, and stresses the disk more than the CPU.

There's no licensing on these scripts. You can do with it whatever you want.

by lunarg on January 10th 2013, at 17:53

You can disable SSL in fetchmail by adding this line to your rc file:

sslproto ssl23

This restricts fetchmail to only use SSLv2 and SSLv3, disabling TLSv1. Note that this will cause the connection to be unencrypted, unless you use a proper SSL plugin, or SSL is requested explicitly.

by lunarg on November 26th 2012, at 17:42

Google Chrome can start up in fullscreen (F11) by default. This is done by enabling Kiosk-mode during startup. To do this, set the shortcut to Chrome like so:

C:\path\to\chrome.exe --kiosk

by lunarg on September 24th 2012, at 12:24
When running dnsmasq inside a VPS on an OpenVZ server, you may get an error while trying to start up dnsmasq (this is in particular the case for Debian):Starting DNS forwarder and DHCP server: dnsmasqdnsmasq: setting capabilities failed: Operation not permitted

This is because dnsmasq does not run as root (which is a good thing). What happens is that dnsmasq gets started as root, then attempts to set privileged functions to the dnsmasq user before changing user from root to that user. When setting these capabilities fails, you get the above error.

The reason for failing is usually because either the kernel is missing the required features, or, in case of OpenVZ, the permissions are not pas  ...

showing posts tagged with 'linux'
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