Posts Tagged ‘version’
Sunday, July 29th, 2012
A friend of mine (Dido) who is learning C programming, has written a tiny chat server / client (peer to peer) program in C. His program is a very good learning curve for anyone desiring to learn basic C socket programming.
The program is writen in a way so it can be easily modified to work over UDP protocol with code:
struct sockaddr_in a;
a_sin_family=AF_INET;
a_sin_socktype=SOCK_DGRAM;
Here are links to the code of the Chat server/client progs:
Tiny C Chat Server Client source code
Tiny C Chat Client source code
To Use the client/server compile on the server host tiny-chat-serer-client.c with:
$ cc -o tiny-chat-server tiny-chat-server.c
Then on the client host compile the client;
$ cc -o tiny-chat-client tiny-chat-client.c
On the server host tiny-chat-server should be ran with port as argument, e.g. ;
$ ./tiny-chat-server 8888
To chat with the person running tiny-chat-server the compiled server should be invoked with:
$ ./tiny-chat-client 123.123.123.123 8888
123.123.123.123 is the IP address of the host, where tiny-chat-server is executed.
The chat/server C programs are actually a primitive very raw version of talk.
The programs are in a very basic stage, there are no condition checks for incorrectly passed arguments and with wrongly passed arguments it segfaults. Still for C beginners its useful …
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Tags: Auto, c programming, c programs, c socket programming, chat client, chat server, checks, client, client host, client server, client source code, codeTo, cThen, curve, dido, Draft, family, ip address, learning c, learning curve, mine, minimalistic, peer to peer program, person, port, program, programming, Protocol, raw version, server c, server client, server host, sockaddr, Socket, socktype, stage, struct, struct sockaddr, Tiny, tiny c, UDP, version, way, writen
Posted in Programming | No Comments »
Sunday, June 17th, 2012
After about 3 years of no new version for GNU / Linux finally Skype has released a new version of Skype.
I thought already there will be never a new skype version out for GNU / Linux, since the moment Microsoft purchased skype.
Now suddenly and quite in quiet the new version of Skype 4.0 is out for download from Skype's website. The latest Skype download for Linux is to be found here
As of time of writting this post there are Skype 4 versions for following Linux-es;;;
- Ubuntu 10.04 32 / 64-bit (probably would work fine on latest Ubuntus too)
- Debian 6.0 Squeeze 32 / 64-bit
- Fedora 16 / 32 bit
- OpenSUSE 12.1 32bit (only)
Most likely the Ubuntu release of skype 4 will work flawlessly on Linux Mint and other debian derivatives.The The release mentions, Skype 4 is supposed to have 4 major advancements and the gap in interface and usability with latest Mac OS and M$ Windows Skype versions is now filled.The four major changes said in the announcement are;;;
Tags: 3 years, anno, audio quality, Auto, bitFedora, Call, chance, Chat, chat history, chats, conversations, czech flag, debian gnu, derivatives, Desktop, download, dpkg, Draft, emoticon, english language support, fedora, gap, Linux, Linux-es, mac os, microphone, Microsoft, minor improvements, mint, nbsp, norwegian flag, phone, quot, Skype, skype download, software, squeeze, support, time, Ubuntu, Ubuntus, usability, version, video, video call, view 3
Posted in Skype on Linux | No Comments »
Friday, March 2nd, 2012
There are four major plugins as of writting of this that can be used to reduce significantly the amount of registration spam in Elgg 1.8.x <= (1.8.3)
Probably there are other plugins to protect against spam in elgg, however I personally tried just this ones to work with elgg 1.8.3..
1. Elgg Anti bot spam registartions with Text Captcha
As you can see in the picture this plugin requires, skills in maths 
For serious websites it also looks a bit ridiculous, besides that is actually an easy one to handle by spam bots, probably plenty of the nowdays spam bots crawling the net could trespass it.
2. Protecting elgg registration formw tih Image Capcha
3. Elgg anti registration spam with Google Captcha
4. Just a Captcha for Elgg 1.8
- Check and Download Elgg Just a Captcha for Elgg here
One note to make here is the 4 Captchas did not work together if enabled from elgg administration panel. You will have to use one at a piece.
I haven't tested to I don't know which one is the most efficient. Anyhow I really think Image Captcha is looking best from all of them and more intuitive to the user.
I'm quite happy Image Captcha is available and works fine in 1.8.3 in prior version 1.6.x generation, I couldn't find any decent plugin to filter login spam and my experimental social network based on elgg, got quickly filled with Spam. Now will wait and see if the Image Captcha will stop the drones.
Tags: administration panel, amount, Anyhow, Auto, Capcha, Captcha, Captchas, Draft, drones, elgg, fine, formw, generation, google, Image, login, lt 1, Math, math text, maths, nbsp, network, network platform, page, panel, platform, plenty, plugin, Protecting, registration, Social, spam, tih, trespass, version, writting, x generation
Posted in Everyday Life, Various, Web and CMS | 1 Comment »
Monday, February 20th, 2012
Already on a couple of mail boxes located on one of the qmail powered mail servers I adminiter, there is an over QUOTA reached problem encountered.
Filling up the mailbox quota is not nice as mails starts get bounced back to the sender with a message QUOTA FULL or EXCEEDED MESSAGE, if this is a crucial mail waiting for some important data etc. the data is never received.
Below is a copy of the mail quota waarning notification message:
Delivered-To: email_use@my-mail-domain.net
Date: Wed, 15 Feb 2012 17:40:36 +0000
X-Comment: Rename/Copy this file to ~vpopmail/domains/.quotawarn.msg, and make appropriate changes
X-Comment: See README.quotas for more information
From: Mail Delivery System <Mailer-Daemon@different.bg>
Reply-To: email@pc-freak.net
To: Valued Customer:;
Subject: Mail quota warning
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 7bit
>
Your mailbox on the server is now more than 90% full. So that you can continue
to receive mail you need to remove some messages from your mailbox.
As you can read from the copy of the mail message above, the message content sent to the mail owner whose quota is getting full is red from /var/vpopmail/domains/.quotawarn.msg
The mail reaching quota problem is very likely to appear in cases like low mailbox quota set, but sometimes also occurs due to bugs in vpopmail quota handling.
Various interesting configuration settings for mail quotas etc. are in /home/vpopmail/etc/vlimits.default file, (assuming vpopmail is installed in /home).
In my specific case, the default vpopmail mailbox quota size was set to only 40 Megabytes.
40MB is too low if compared to todays mailbox size standards which in Gmail and Yahoo mail services are already a couple of gigabytes.
Hence to get around the quota troubles, I removed the quota for the mail.
To remove the quota size in vpopmail set for address (email_user@my-mail-domain.net) used cmd:
qmail-server:~# vmoduser -q NOQUOTA email_user@my-mail-domain.net
To save myself from future quota issues, I decided to apply a permanent fix to all those over quota size VPOPMAIL mailbox problems by removing completely quota restriction for all mailboxes in my vpopmail existent mail domain.
To do so, I wrote a quick simple bash loop one-liner script:
qmail-server:~# cd /home/vpopmail/domains
qmail-server:~/vpopmail/domains# cd my-mail-domain.net
qmail-server:~/vpopmail/domains/my-mail-domain.net# for i in *; do \
vmoduser -q NOQUOTA $(echo $i|grep -v vpasswd)@my-mail-domain.net; \
done
This works only on vpopmail installations which are configured to store the mail messages directly on the filesystem. Therefore this approach will not work for people who during vpopmail install had configured it to store mailboxes in MySQL or in other kind of SQL db engine.
Anyways for Vpopmail installed to use SQL backend, the script can be changed to read directly a list with all the mailboxes obtained from databasae (SQL query) and then, loop over each of the mail addresses apply the vmoduser -q NOQUOTA mail@samplemaildomain.net.
I've written also a few lines shell script (remove_vpopmail_emails_domain_quota.sh), it accepts one argument which is a vpopmail domain to which the admin would like to reset all applied mailbox quotas. The script is useful, if you have to often remove all quotas for vpopmail domainsor have to do quota wipe out simultaneously for multiple email domain names located on different servers.
Tags: Auto, bit, charset, configuration settings, content transfer, copy, Date, Draft, EXCEEDED, file, free mail services, FULL, gigabytes, Gmail, information, ISO, mail boxes, mail delivery system, mail domain, mail message, mail owner, mail quota, mail quotas, mail server, mail servers, mail services, mailbox quota, mailbox size, megabytes, message, message quota, Mime, msg, msgThe, nbs, NOQUOTA, notification message, Qmail, quot, quota problem, README, Rename, script, sender, size, SQL, text, transfer, version, vpopmail
Posted in Qmail, System Administration | No Comments »
Thursday, February 2nd, 2012
I'm managing few wordpress installations which requires me to type in:
Hostname , FTP Username and FTP Password , every single time a plugin update is issued and I want to upgrade to the new version.
Below is a screenshot of this annoying behaviour:
As you can see in the above screenshot, there is no way through Update Plugins web interface to store the password permanently. Hence the only option to store it permanently is to manually edit wp-config.php (file located in wordpress docroot, e.g. /path/to/wordpress/wp-config.php , inside the file find the line:
define ('WPLANG', '');
Right after it put a code similar to:
define('FS_METHOD', 'ftpsockets');
define('FTP_BASE', '/path/to/wordpress/');
define('FTP_CONTENT_DIR', '/path/to/wordpress/wp-content/');
define('FTP_PLUGIN_DIR ', '/path/to/wordpress/wp-content/plugins/');
define('FTP_USER', 'Username');
define('FTP_PASS', 'Password');
define('FTP_HOST', 'localhost');
Change the above defines:
path/to/wordpress/ – with your wordpress location directory.
Username and Password – with your respective FTP username and password. The localhost
That's all, from now onwards the User/Password prompt will not appear anymore. Consider there is a security downside of storing the FTP User/Pass in wp-config.php , if someone is able to intrude the wordpress install and access the documentroot of the wordpress install he we'll be able to obtain the ftp user/pass and log in the server directly via FTP protocol.
Tags: Auto, base path, behaviour, config, content, documentroot, downside, Draft, file, g path, host, line, localhost, location, location directory, password, Path, php, plugin, Protocol, screenshot, security, someone, time, type, update, User, version, way, web interface
Posted in System Administration, Web and CMS, Wordpress | No Comments »
Friday, January 27th, 2012
By default latest Debian GDM does not provide an automatic way to login using user AVATARS (like Windows does).
This is pretty strange, especially if you compare to Ubuntu and many other Linux distributions which already has support for AVATAR login via GDM
The reason for this is that currently Debian is shipped with old version of gdm2 and this gdm version does not have support for clickable login avatars.
Debian looks by default like this:
Thanksfully this non-user friendly GNOME login screen behaviour can be changed by simply installing gdm3
root@debian:~# apt-get --yes install gdm3
...
This will remove the old gdm installed package as well as fast-user-switch-applet and install the gdm3.
Having installed the gdm3 with configured a background will look like so:
I was quite stunned that gdm3 does not have included support for themes . As far as I've spoken with some ppl in irc.freenode #gnome the reason for this oddity is it crashed a lot when a theme is configred.
By default the gdm2 themes are provided by a package called gdm-themes, since gdm3 does not support themes (yet), the package gdm3-themes is missing.
Tags: avatar, avatars, behaviour, Debian, debian gnu, freenode, GDM, Gnome, gnu linux, Linux, linux distributions, login, nbsp, non-user, oddity, old version, package, ppl, reason, root, screen, squeeze, support, support themes, Thanksfully, theme, Ubuntu, version, way
Posted in Gnome, Linux, Linux and FreeBSD Desktop, Various | No Comments »
Monday, January 23rd, 2012
Every now and then my gnome keyboard layout switcher hangs. When my keyboard switcher hangs I can't switch between my two defined languages English and my native Bulgarian
The hang up of the language switcher is makes switching between my two defined languages impossible until I logoff and login again or kill the current GNOME session with CTRL+ALT+BACKSPACE.
Sometimes logging off again is not necessery so I have to logoff and login to GNOME few times until finally the gnome keyboard layout switcher reacts to an issued change language via Alt+Shift or by clicking on it.
Unfortunately the gnome keyboard layout switcher is not available as a process so there is no way to simply kill -HUP the process responsible for it.
Just until today I couldn't find a way how to restart the gnome keyboard layout switcher when it hangs.
Now today I finally found a way to restart it without restarting the whole gnome session or killing completely the Xorg server.
To "fix" up the keyboard switcher when its not responding, I had to issue in gnome-terminal or via ALT+F2:
hipo@noah:~$ gnome-keyboard-properties
As you can see in the screenshot below, one has to press the Move Up button to switch the default order of languages. Once this is done the keyboard layout switcher starts working again. Once working I just used the move up once again to revert back my default language order as it used to be.
I'm not sure what exactly is causing the GNOME 2 keyboard layout switcher to hang (when it does), my guess is it is due to some kind of version incompitability between gnome versions or configurations specific to my computer. In the past I was running Debian Testing/Unstable and then downgraded back to Debian stable, probably this is the reason of the language switcher hangs.
Tags: Button, change, change language, Computer, default language, f2, Gnome, guess, hipo, HUP, incompitability, keyboard layout, keyboard switcher, kind, languages, layout, login, move, necessery, noah, order, reason, revert, screenshot, switch, switcher, testing, today, Unstable, version, way
Posted in Gnome, Linux, Linux and FreeBSD Desktop, Linux Audio & Video | No Comments »
Thursday, January 5th, 2012
While checking a friend of mine's blog, I've seen a reference to a Windows program capable of revealing stored website passwords.
IE PassView is a small password management utility that reveals the passwords stored by Internet Explorer Web browser, and allows you to delete passwords that you don't need anymore. It supports all versions of Internet Explorer, from version 4.0 and up to 9.0.
Ie PassView is quite a good one for crackers, who would like to steal some lame poor Windows IE user facebook,gmail, yahoo etc. passwords here is a link to IE Passview's download page
Tags: Auto, blog, browser, crackers, download, download page, Draft, explorer, explorer web browser, facebook, Gmail, internet explorer web, link, management utility, Microsoft, mine, page, PassView, password, password management, passwords, poor, reference, utility, version, view, website, Windows, windows program, Yahoo
Posted in Computer Security, Windows | 1 Comment »
Sunday, December 25th, 2011
There is a brand new remote FreeBSD vulnerability in telnetd in all its versions starting from version 7 to 9. It is therefore advisable that the telnet daemon be completely disabled.
To disable telnetd on FreeBSD:
1. Open /etc/inetd.conf
freebsd# vi /etc/inetd.conf
2. Comment out the line
telnet stream tcp nowait root /usr/libexec/telnetd telnetd
e.g.:
#telnet stream tcp nowait root /usr/libexec/telnetd telnetd
3. Restart inetd
freebsd# /etc/rc.d/inetd restart
The whole remote root telnetd FreeBSD security advisory (SA), can be read here
Tags: brand, Comment, conf, daemon, freebsd, freebsd security, inetd, libexec, line, line telnet, nowait, Restart, root, security, security advisory, stream, tcp, Telnet, telnetd, usr, version, vulnerability
Posted in Computer Security, FreeBSD, System Administration | 2 Comments »
Friday, December 9th, 2011
I have few servers, which have automatically enabled IPv6 protocols (IPv6 gets automatically enabled on Debian), as well as on most latest Linux distribituions nowdays.
Disabling IPv6 network protocol on Linux if not used has 2 reasons:
1. Security (It's well known security practice to disable anything not used on a server)
Besides that IPv6 has been known for few criticil security vulnerabilities, which has historically affected the Linux kernel.
2. Performance (Sometimes disabling IPv6 could have positive impact on IPv4 especially on heavy traffic network servers).
I've red people claiming disabling IPv6 improves the DNS performance, however since this is not rumors and did not check it personally I cannot positively confirm this.
Disabling IPv6 on all GNU / Linuces can be achieved by changing the kernel sysctl settings net.ipv6.conf.all.disable_ipv6 by default net.ipv6.conf.all.disable_ipv6 equals 1 which means IPv6 is enabled, hence to disable IPv6 I issued:
server:~# sysctl net.ipv6.conf.all.disable_ipv6=0
To set it permanently on system boot I put the setting also in /etc/sysctl.conf :
server:~# echo 'net.ipv6.conf.all.disable = 1 >> /etc/sysctl.conf
The aforedescribed methods should be working on most Linux kernels version > 2.6.27 in that number it should work 100% on recent versions of Fedora, CentOS, Debian and Ubuntu.
To disable IPv6 protocol on Debian Lenny its necessery to blackist the ipv6 module in /etc/modprobe.d/blacklist by issuing:
echo 'blacklist ipv6' >> /etc/modprobe.d/blacklist
On Fedora / CentOS there is a another universal "Redhat" way disable IPv6.
On them disabling IPv6 is done by editting /etc/sysconfig/network and adding:
NETWORKING_IPV6=no
IPV6INIT=no
I would be happy to hear how people achieved disabling the IPv6, since on earlier and (various by distro) Linuxes the way to disable the IPv6 is probably different.
Tags: blackist, boot, Cannot, CentOS, conf, Debian, Disabling, distro, DNS, fedora, gnu linux, heavy traffic, impact, ipv, ipv4, ipv6, kernel, kernel 2, Linux, linux kernel, linux kernels, methodology, modprobe, Module, necessery, net, network, network protocol, network servers, Networking, number, performance, Protocol, protocols, quot, Redhat, security, security practice, security vulnerabilities, sysctl, system boot, traffic network, Ubuntu, version, way
Posted in Linux, System Administration | No Comments »
on 
on 
How to turn off telnetd on FreeBSD
Sunday, December 25th, 2011There is a brand new remote FreeBSD vulnerability in telnetd in all its versions starting from version 7 to 9. It is therefore advisable that the telnet daemon be completely disabled.
To disable telnetd on FreeBSD:
1. Open /etc/inetd.conf
freebsd# vi /etc/inetd.conf
2. Comment out the line
telnet stream tcp nowait root /usr/libexec/telnetd telnetd
e.g.:
#telnet stream tcp nowait root /usr/libexec/telnetd telnetd
3. Restart inetd
freebsd# /etc/rc.d/inetd restart
The whole remote root telnetd FreeBSD security advisory (SA), can be read here
Tags: brand, Comment, conf, daemon, freebsd, freebsd security, inetd, libexec, line, line telnet, nowait, Restart, root, security, security advisory, stream, tcp, Telnet, telnetd, usr, version, vulnerability
Posted in Computer Security, FreeBSD, System Administration | 2 Comments »