Technical and commercial comparison of Citrix XenServer and VMware

Tags

citrix, vmvare

Citrix XenServer and VMware vSphere are two leading server
virtualization platforms. This document provides a technical and
commercial comparison of XenServer and vSphere, including
installation and maintenance, OS support, high availability,
disaster recovery and other important virtualization concerns that
should be weighed when exploring virtualization solution options.

Get the White Paper here.

 

 

MeGUI video encoder

Tags

containers, encoder, mpeg 4, video

MeGUI is the most comprehensive GUI based ISO MPEG-4 solution. It suports MPEG-4 ASP (xvid), MPEG-4 AVC (x264), AAC, MP2, MP3, Flac, Vorbis, AC3 audio and various common containers support (MP4, MKV, AVI, M2TS).

http://sourceforge.net/projects/megui/

http://mewiki.project357.com/wiki/Main_Page

VMWare vSphere – Demystifying what is FREE

Tags

comparison, difference, free, hypervisor, paid, vmware, vsphere, vsphere-paid-vs-free

FREE: VMware vSphere Hypervisor   (Also known as ESXi)

ADV: Free  VMware vSphere Client to administer the server

DISAD: Cannot be managed with vCenter or other management solutions

COMMERCIAL: VMware vSphere

ADV: advanced functionally including centralized management, live migration of virtual machines, automatic load balancing, business continuity, power management, and backup and restore capabilities for virtual machines.

Hence, The extra word “Hypervisor” in the product name is the mystery & decides which one is free & which one must be purchased.

Free can be upgraded by putting a license.

Source:

http://www.vmware.com/products/vsphere-hypervisor/faq.html

Tux Happy Holidays

Tags

greetings, linux, tux

The Tao of UBUNTU

Tags

linux, quote, tao, ubuntu

A person with ubuntu is open and available to others, affirming of others, does not feel threatened that others are able and good, for he or she has a proper self-assurance that comes from knowing that he or she belongs in a greater whole and is diminished when others are humiliated or diminished, when others are tortured or oppressed.

~ Archbishop Desmond Tutu, 1999

Source: http://ubuntuforums.org/showthread.php?t=1016501

get a free techie custom email address

Tags

address, bsd, custom, email, free, linux, techie

do you want  an email address that look more professional ? one that make you feel techie?

while digging deeper in google, i found some free email providers:

mail.com

The main drawback: no option to forward mail to another account such as gmail (feature available in premium account)
You can create email account in the form:

name@linuxmail.org
name@bsdmail.com
name@techie.com
name@programmer.net
name@hackermail.com

There is more to choose from.You will find a long list when you sign up.

easy.la

Good news is that it allows to forward to another account (as specified on their website).
You can create email account in the form:

name@admin.la

Again,there is more to choose from.You will find a long list when you sign up.

Wireshark Remote Capture using X-Forwarding

Tags

capture, remote, wireshark, x-forwarding

Because I was not very satisfied with the results of googling “wireshark remote capture x forwarding”, I wrote this little tutorial for my happiness.

1. To enable X11 forwarding on the server you need at least the xauth  program.
On the remote server install the following:

apt-get install xserver-xorg

apt-get install xbase-clients

apt-get install wireshark

2. on local machine:

# ssh -X root@remotemachine
# wireshark

3. Go to Capture > Options > Interface > Pseudo-Device

linux: reset iptables firewall rules

Tags

delete, iptables, reset, rules

Create a shell script (iptables_flush.sh) and copy paste the following lines:

#!/bin/sh
echo "Flushing iptables rules..."
sleep 1
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

Make the file executable

chmod +x iptables_flush.sh

and run the script:

./iptables_flush.sh

Source:

http://insanelabs.com/linux/linux-reset-iptables-firewall-rules/

postfix per recipient sender restrictions

Tags

postfix, recipient, restrictions, sender

The following is taken from the official postfix documentation:

Protecting internal email distribution lists

We want to implement an internal email distribution list. Something like all@our.domain.com, which aliases to all employees. My first thought was to use the aliases map, but that would lead to “all” being accessible from the “outside”, and this is not desired…

Postfix can implement per-address access controls. What follows is based on the SMTP client IP address, and therefore is subject to IP spoofing.

/etc/postfix/main.cf:
    smtpd_recipient_restrictions =
        check_recipient_access hash:/etc/postfix/access
        ...the usual stuff...

/etc/postfix/access:
    all@my.domain   permit_mynetworks,reject
    all@my.hostname permit_mynetworks,reject

Specify dbm instead of hash if your system uses dbm files instead of db files. To find out what map types Postfix supports, use the command postconf -m.

Now, that would be sufficient when your machine receives all Internet mail directly from the Internet. That’s unlikely if your network is a bit larger than an office. For example, your backup MX hosts would “launder” the client IP address of mail from the outside so it would appear to come from a trusted machine.

In the general case you need two lookup tables: one table that lists destinations that need to be protected, and one table that lists domains that are allowed to send to the protected destinations.

What follows is based on the sender SMTP envelope address, and therefore is subject to SMTP sender spoofing.

/etc/postfix/main.cf:
    smtpd_recipient_restrictions =
        check_recipient_access hash:/etc/postfix/protected_destinations
        ...the usual stuff...

    smtpd_restriction_classes = insiders_only
    insiders_only = check_sender_access hash:/etc/postfix/insiders, reject

/etc/postfix/protected_destinations:
    all@my.domain   insiders_only
    all@my.hostname insiders_only

/etc/postfix/insiders:
    my.domain       OK  matches my.domain and subdomains
    another.domain  OK  matches another.domain and subdomains

Getting past this scheme is relatively easy, because all one has to do is to spoof the SMTP sender address.

If the internal list is a low-volume one, perhaps it makes more sense to make it moderated.

PLEASE NOTE:

To get this working you have to perform these additional steps.

1.You need to run postmap to create the database:

# postmap /etc/postfix/protected_destinations
# postmap /etc/postfix/insiders

2. Restart postfix :

# /etc/init.d/postfix restart

Source: http://www.postfix.org/RESTRICTION_CLASS_README.html

multi-row vs multiple inserts postgresql

Tags

insert, optimization, performance, sql, tuning, tweaking

While doing a research on improving the INSERT performance on PostgreSQL  i found the following useful links:

http://kaiv.wordpress.com/2007/07/19/faster-insert-for-multiple-rows/

http://stackoverflow.com/questions/1793169/which-is-faster-multiple-single-inserts-or-one-multiple-row-insert

N.B:If you played around or tested it , please share your experience.