Syndicate content

Unix

An Operating System that works. All the specifications are free and Linux, AIX, HP-UX, SunOS, Solaris, IRIX are examples of a Unix implementation.

Attacks by ZmEu or w00tw00t robots

Who is ZmEu?

An image showing ZmeuThe name Zmeu (no capital E) is the name of a fantastic creature of Romania. There are so many stories that there isn't a clear understanding of what it is... but it is human like, can spit fire and wants to marry young women.

If you're wondering, it is generally a bad guy.

ZmEu Attack

Today, I noticed a lot of traffic on one of my servers. Looking into what was happening, I immediately found out that an attacker was looking for a loophole in that system. That attack was being performed from China.

Old Synergy 64bit version for windows compatible with Ubuntu synergy package version 1.4.12

As I like to have Synergy working on my Windows boxes (i.e. laptops), I am saving a copy of the installer 64 bit version which works fine with WinXP and Win7. I'm about to test it with Win10 which is likely to accept it as is too. Just in case you did not know, Synergy is a driver that takes one mouse device and makes it work on multiple computers. In other words, you can use any number of computers with one mouse and one keyboard. Move the mouse to the right computer and you can use the keyboard on that computer. No need for a KVM anymore (Keyboard Video Mouse device that allowed you to ...

How to setup a Linux firewall

Introduction

If you setup a Linux box, you want to setup a firewall before you connect your computer to the Internet. If you are setting up a remote server, it should only have the SSH port open. Connect to it, setup the fire, then only install the other servers and open ports as required (and only ports that need to be connected from the outside.)

Any port that you open without the firewall already setup is at risk. You may want to install PHP and along will come a database which may open a port to the Internet. Something that you just don't want to happen.

Setup Firewall

To ...

Turning sites and modules on and off in Apache2

I always have to looks for the command line option to turn sites and modules on and off (really it is said to be enabled or disabled.)

The commands are as follow:

  • a2ensite -- enable one site
  • a2dissite -- disable one site
  • a2enmod -- enable one module
  • a2dismod -- disable one module

When you use one of the commands in the command line terminal without specifying which site or module to enable, then you are given a list of the sites or modules you can enable or disable. Note that the configuration files have to end with .conf for this mechanism to work as expected.

How do you get micro-seconds from the Linux stat(2) call?

A little while ago I noticed that I couldn't find documentation on how to get the modification time of a file in micro-seconds. The notorious stat() call returns st_mtime defined as a time_t in the documentation.

Well... The fact is that the structure is really composed of a timeval structure and not a time_t (that applies to all 3 time values: modification, last access, and last status change.) So in fact you can use the name of the field without the last letter and a sub-timeval field as in:

struct stat s;
seconds = s.st_mtim.tv_sec; // == s.st_mtime
microseconds = ...

Lost SSH key graphical prompt and auto-add to SSH agent

At some point in the past, my system somehow lost the ability to avoid asking me for my key every time I connect to one of my servers. It generally okay, I don't do so much work on that server that I'd have to connect all the time...

However, it is annoying when, once in while, I end up doing a lot of work, back and forth.

The ssh-agent was installed and working. I could add the key manually:

ssh-add ~/.ssh/my-secret-key
ssh-add -l

The ssh-add command allows you to add and remove keys from the ssh-agent. The -l command line option lists the keys currently held by the agent.

...

Supermicro X9SCI/X9SCA, video is gone!

As I am still trying to get my computers to work with a dual seat (or multiseat), I did an attempt in using the onboard video (a relatively decent Matrox card.) So I went in the BIOS and changed the setup for the video from Offboard to Onboard. Big mistake!

The video stopped working. On reboot the computer beeped 8 times and booted the OS normally (I have SSH setup so I could access the computer, but absolutely no video on either port: on board and off board.)

I have a Supermicro X9SCI/X9SCA. Searching for "no video" or "missing video on boot"... returned nothing ...

How to only upgrade packages with a security requirement in Ubuntu/Debian?

Today I wanted to upgrade some packages that had security issues. Ubuntu (like Debian) provides the apt-get tool that allows you to do upgrades the easy way:

sudo apt-get upgrade

However, that upgrades all the packages present. In some cases, you may want to skip on some packages because you know they are not ready (i.e. your own packages).

In order to only upgrade security issues, you want to get a list of packages that are to be upgraded for security issues:

apt-get -s dist-upgrade | grep "^Inst" | grep -i securi

That apt-get command line lists all the packages ready for ...

no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory

As I upgrade to 14.04, I started seeing this error in my console:

no talloc stackframe at ../source3/param/loadparm.c:4864, leaking memory

Quite cryptic if you ask me, but the "leaking memory" did sound bad.

The error would in particular appear when I used sudo for whatever reason, for example:

sudo iptables -L -nvx

So... something to do with sudo?

I found the answer on the Ubuntu forum. The solution is to turn off a feature of samba. Run the samba setup tool in your console:

sudo pam-auth-update

That opens a curses window in your console. You should then see an option ...

Update to Ubuntu 14.04, huge problems with the display!

Oka, so today I finally got the chance to upgrade to Ubuntu 14.04, hopefully soon to 14.10 too.

I have to say that in general, it looks like they've done a good job as things seem to work better...

However, the display setup got lost. My HP 2509m monitor is connected through a KVM and because of that, it does not always work as expected. That is, the nVidia card does not get to read the monitor information. It took me a while, but I found a way to fix the problem.

First of all I connected the monitor directly to my computer. That gave me the ability to change the resolution to 1920x1080 ...

Syndicate content Syndicate content

     

Terms of Site Index

Find the page/content you are looking for with our index.

  • CPU
    Central Processing Unit--what actually enables a computer to do things. The most well known are the Intel and AMD processors, although there are thousands of them.
  • Fedora

    Linux system based on the now discontinued free RedHat distribution. Previously called FedoraCore.

  • footer

    The bottom of a page, generally something that appears on all the pages such as the current page number, total number of pages, date when it was printed, and the name of the company.

  • row
  • URL