Introduction
Security, always a concern in these days, yes, it may be your house, your car even yourself, we are all in danger, and so are our servers and computers.
Well, to protect you Linux computer you can take a lot of actions, and one of them is to know which ports is your Linux listening to, this way if some of them are not needed you can shut the service down.
Which ports is my Linux listening to?
We’ll use netstat to find out which ports is our computer listening to.
netstat -t --listening
The output could look like this:
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:x11 *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 *:ipp *:* LISTEN
tcp 0 0 *:microsoft-ds *:* LISTEN
tcp 0 0 *:netbios-ssn *:* LISTEN
tcp 0 0 *:x11 *:* LISTEN
tcp 0 0 *:ipp *:* LISTEN
That is the example of my office computer, your output may change, and if it is a public server, you should have a lot less ports opened.
Tuesday, April 26, 2011
Find alive hosts in a network with ICMP nmap
Introduction
If you want to know which servers or hosts are alive and responding to ping in your local network, you can use nmap
Using nmap to discover ‘alive’ machines on a Network
To use this command and get an effective response, the servers or hosts you are pinging need to respond to it, today a lot of hosts by default have a firewall, and will not respond to pings, so be aware of that.
The command is:
nmap -sP 10.1.1.*
This will have a response like this:
Nmap scan report for 10.1.1.1
Host is up (0.0060s latency).
Nmap scan report for 10.1.1.192
Host is up (0.0023s latency).
Nmap scan report for 10.1.1.193
Host is up (0.061s latency).
Nmap scan report for 10.1.1.198
Host is up (0.0046s latency).
Nmap scan report for 10.1.1.200
Host is up (0.0044s latency).
Nmap scan report for 10.1.1.254
Host is up (0.030s latency).
Nmap done: 256 IP addresses (6 hosts up) scanned in 2.94 seconds
Those are the machines on, in a holy day at my office.
If you want to know which servers or hosts are alive and responding to ping in your local network, you can use nmap
Using nmap to discover ‘alive’ machines on a Network
To use this command and get an effective response, the servers or hosts you are pinging need to respond to it, today a lot of hosts by default have a firewall, and will not respond to pings, so be aware of that.
The command is:
nmap -sP 10.1.1.*
This will have a response like this:
Nmap scan report for 10.1.1.1
Host is up (0.0060s latency).
Nmap scan report for 10.1.1.192
Host is up (0.0023s latency).
Nmap scan report for 10.1.1.193
Host is up (0.061s latency).
Nmap scan report for 10.1.1.198
Host is up (0.0046s latency).
Nmap scan report for 10.1.1.200
Host is up (0.0044s latency).
Nmap scan report for 10.1.1.254
Host is up (0.030s latency).
Nmap done: 256 IP addresses (6 hosts up) scanned in 2.94 seconds
Those are the machines on, in a holy day at my office.
Wednesday, April 13, 2011
6 reasons why I hate Facebook | Why this Great Website- Facebook Sucks
Facebook may be a big social networking site, but it’s not the best. OK; it can be a great web traffic source and you can get immediate exposure for your posts. These are pretty strong causes, why you would love Facebook. But not today. Now you will see, why this “great” website sucks.
Annoying ads
You may heard of Facebook ads. It’s based on the CPC (cost-per-click) and the CPM (cost-per thousands of impressions). There is no set cost for Facebook Ads. You can decide how much you’d like to spend for your marketing campaign. This is very impressive if you are an advertiser, but if you are an average user, these adverts are irritating. Every time you visit a FB page, in the sidebar there are about 5 ad blocks with a “Like” button under every one.
Privacy problems
Now there are loads of privacy options. But would you really trust a business orientated company? Maybe yes, maybe no. It’s your decision.
There are better social networking sites
Frankly I think Twitter is better. Of course there are limitations there as well. You can’t tweet a message more than 140 characters. But it is a great way to reach a targeted audience. Also Hi5 and LinkedIn are good if you want to get awesome results for your business or your blog.
“Spammy” emails
Here is my little story: I didn’t use Facebook for about one month. But nearly every time I viewed my email inbox, I got an email titled: “Getting back onto Facebook”. It always said:
Hi …..,
Sorry you’ve been having trouble logging into your Facebook account.
GET BACK ON FACEBOOK NOW!
Of course I didn’t try to sign in to Facebook. So all of those mails were scam.
Like to view the content
Every time I would like to view a page that interests me, it tells me, you have to Like to view all content. This is a quite simple marketing tactic. Getting users to register, to get access to anything. But what if I wouldn’t like to sign up? What if I don’t want to give information about myself?
I’m sick of the Facebook orientated world
“I will go to play football on Saturday. Can you come? Write to me on Facebook if you’re coming.“
“Can you give me the Maths homework on Facebook?”
“I will give you the link of my website on Facebook!”
Why do we need this website? OK; it’s good and nice, but that’s it. Everything is that’s it…
So if I would like to summarize this social network, I would say today it is good but tomorrow it will end up like MySpace, forgotten.
Tuesday, April 12, 2011
Monday, April 11, 2011
Sunday, April 10, 2011
Thursday, April 7, 2011
BIRTH OF THE FAMOUS NAMES....!!!
The name started as a joke boasting about the amount of information the search-engine would be able to search. It was originally named 'Googol', a word for the number represented by 1 followed by 100 zeros. After founders- Stanford graduate students Sergey Brin and Larry Page presented their project to an angel investor, they received a cheque made out to 'Google' ...thus the name.
Founder Jack Smith got the idea of accessing e-mail via the web from a computer anywhere in the world. When Sabeer Bhatia came up with the business plan for the mail service, he tried all kinds of names ending in 'mail' and finally settled for hotmail as it included the letters "html" - the programming language used to write web pages. It was initially referred to as HoTMaiL with selective uppercasing.
Bill Hewlett and Dave Packard tossed a coin to decide whether the company they founded would be called Hewlett-Packard or Packard-Hewlett.
INTEL
Mitch Kapor got the name for his company from 'The Lotus Position' or 'Padmasana'. Kapoor used to be a teacher of Transcendental Meditation of Maharishi Mahesh Yogi.
ORACLE
Oracle (the CIA saw this as the system to give answers to all questions or something such). The project was designed to help use the newly written SQL code by IBM. The project eventually was terminated but Larry and Bob decided to finish what they started and bring it to the world. They kept the name Oracle and created the RDBMS engine. Later they kept the same name for the company.
SUN
Founded by four Stanford University buddies, SUN is the acronym for Stanford University Network. Andreas Bechtolsheim built a microcomputer; Vinod Khosla recruited him and Scott McNealy to manufacture computers based on it, and Bill Joy to develop a UNIX-based OS for the computer.
The word was invented by Jonathan Swift and used in his book 'Gulliver's Travels'. It represents a person who is repulsive in appearance and action and is barely human. Yahoo! Founders Jerry Yang and David Filo selected the name because they considered themselves yahoos.
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