Unix Commands

Is a Google Talk Contact Invisible? Sometimes error messages can reveal more than they were supposed to. Rahul Bansal writes about a simple trick that helps you find out if one of your Google Talk contacts is offline or uses the invisible mode. The trick takes advantage of Google's off the record feature which lets you chat with your contacts without saving the conversations in Gmail. "Chats that have been taken off the record aren't stored in your Gmail chat history, or in the Gmail chat history of your contact. You and the person you're talking to can both see when a chat is taken off the record, and you'll be notified if off the record mode is disabled. Your off the record settings will apply whenever you chat with this person, until one of you makes a change." Let's say you want to know if your co-worker Michael is really offline. If you start a chat when he is online and select "go off the record", none of your messages will be saved in Mi...

HACK YAHOO MESSENGER AND GOOGLE TALK TO OPEN MULTIPLE INSTANCES HERE’s a simple hack for yahoo messenger and google talk through which u can create multiple instances if in case u need to.. FOR YAHOO MESSENGER Go to Start -> Run -> Type regedit -> hit enter Go to HKEY_CURRENT_USER->> Software ->> Yahoo ->> pager ->>Test Right click on test -> choose new Dword value . Rename it as Plural. Double click it -> assign a decimal value of 1. Close registry -> Restart yahoo messenger. NOW you can open yahoo messenger N number of times FOR GOOGLE TALK Create a shortcut of Google Talk messenger on your desktop or any other location. Right click on the Google Talk messenger icon and select properties option Modify target location text by this “c:\program files\google\google talk\googletalk.exe” / startmenu to “c:\program files\google\google talk\googletalk.exe” / nomutex Click OK Now you can run multiple...

What is SSH SSH (Secure SHell) is a network protocol which provides a replacement for insecure remote login and command execution facilities, such as telnet, rlogin and rsh. SSH encrypts traffic in both directions, preventing traffic sniffing and password theft. SSH also offers several additional useful features: • Compression: traffic may be optionally compressed at the stream level. • Public key authentication: optionally replacing password authentication. • Authentication of the server: making ”man-in-the-middle” attack more difficult • Port forwarding: arbitrary TCP sessions can be forwarded over an SSH connection. • X11 forwarding: SSH can forward your X11 sessions too. • File transfer: the SSH protocol family includes two file transfer protocols. Basic SSH usage Remote login The basic syntax to log into a remote host is: ssh hostname If you want to specify a username, you may do it using an rlogin-compatible format: ssh -l user ho...

How to find number of processors in linux $cat /proc/cpuinfo | grep processor processor : 0 processor : 1 It has two logical processors $cat /proc/cpuinfo|grep physical physical id : 0 physical id : 0 It has single physical processor Processor: Intel dual core Janu

Why do I need so many IP addresses to set up fault tolerance? There are three 'classes' of IP addresses that we use: 1) 'Front-end' IP addresses - think of these as what are the current IP addresses of each of the Load Balancer machines. Each machine must have a unique IP address to identify itself, so you can contact it directly. '2) Traffic' IP addresses - these are the addresses of your load balancers that the outside world will see and know about. You need at least two of these (so the balancers can have an address each). Unlike the 'front-end' IP addresses, traffic IP addresses are not tied to one machine - they get shared around and moved. For instance, if one of the balancer machines dies, then the other balancer will take its traffic IP address. This way, visitors will always be able to reach your site. '3) Back-end' IP addresses - the balancer machines use these IP addresses to contact the back-end servers. The balancer...

As the popularity of the Internet grew, businesses turned to it as a means of extending their own networks. First came intranets, which are password-protected sites designed for use only by company employees. Now, many companies are creating their own VPN (virtual private network) to accommodate the needs of remote employees and distant offices. A typical VPN might have a main LAN at the corporate headquarters of a company, other LANs at remote offices or facilities and individual users connecting from out in the field. http://computer.howstuffworks.com/vpn2.htm Basically, a VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together. Instead of using a dedicated, real-world connection such as leased line, a VPN uses "virtual" connections routed through the Internet from the company's private network to the remote site or employee. In this article, you will gain a fundamental understanding of VPNs, and ...

Domain Names Because most people have trouble remembering the strings of numbers that make up IP addresses, and because IP addresses sometimes need to change, all servers on the Internet also have human-readable names, called domain names. For example, www.howstuffworks.com is a permanent, human-readable name. It is easier for most of us to remember www.howstuffworks.com than it is to remember 209.116.69.66. The name www.howstuffworks.com actually has three parts: 1. The host name ("www") 2. The domain name ("howstuffworks") 3. The top-level domain name ("com") Domain names within the ".com" domain are managed by the registrar called VeriSign. VeriSign also manages ".net" domain names. Other registrars (like RegistryPro, NeuLevel and Public Interest Registry) manage the other domains (like .pro, .biz and .org). VeriSign creates the top-level domain names and guarantees that all names within a top-level domain are unique. VeriSign also m...