MyIpTest.com,Online Free IP tools

How can I find other person IP Address ?

Mon, 13 Apr 2009 14:30:07 +0100

Why I need this tool ?

If you want to get IP address of some person you talk on yahoo IM, skype, email, or other You can use this tool to find person IP address.

How to use this tool ?

You can see on top of this page there are 2 generated links. First link is for person you want to find IP address, the second one is for you. First you need to copy first link and send it to that person you want to get IP address. Then, using second link you can find person IP address if that person clicked on first link.

How can I hide this long link ?

You can use http://tinyurl.com/ to make this link shorter and more credible.

Tool link: http://www.myiptest.com/staticpages/index.php/how-about-you

How do I change MAC Address ?

Mon, 13 Apr 2009 09:40:47 +0100

How to change a MAC address in Microsoft Windows

Under Windows, the MAC address is stored in a registry key. To change a MAC address, find that key with `regedit` and change it. Of course, Microsoft keeps moving the location of the key around!

Windows XP adds an option to change the MAC address on some network cards under the Advanced tab in the network adapter's Properties menu.

A much easier and more reliable method to change a MAC address under Windows is to use a software utility program designed to do this for you.

Macshift is a free utility that you can use to spoof your MAC address under Microsoft Windows

How to change a MAC address in MacOS

Instructions for changing the MAC address on a Macintosh can be found at MAC Spoofing on the Macintosh.

How to change a MAC address in FreeBSD

In FreeBSD, you can change your MAC address with the `ifconfig <interface> link <address>` command.

How to change a MAC address in Linux

Under Linux, you can change your MAC address with `ifconfig <interface> hw <class> <address>`, or you can use the GNU MAC Changer.

How to change a MAC address in Solaris

In Solaris, you can change the MAC address with the `ifconfig <interface> <ether> <address>` command.

How to change a MAC address in OpenBSD

OpenBSD does not, by default, allow you to change the MAC address. It is possible to change the MAC address under OpenBSD with sea.c.

How to change a MAC address in HP-UX

Under HP-UX, you can change the MAC address in SAM by selecting Networking and Communications, then selecting the interface, then Action, Modify, Advanced Options. HP-UX refers to the MAC address as the "station address".

source: http://www.tech-faq.com/change-mac-address.shtml

How to use Proxy server?

Thu, 09 Apr 2009 18:38:47 +0100

The following are instructions to configure various browsers to use an http proxy server.

First you need proxy.

Get it here: www.myiptest.com/proxy

also you can find good proxy servers here: http://www.proxyfire.net/

For Firefox you can use plugin SwitchProxy, the best one http://mozmonkey.com/switchproxy/

Instructions for Firefox 3.0

Select the Tools Menu
Select Options
Select the Advanced Icon
Select the Network tab
Under connection select Settings
Under Settings you can chose "Auto-Detect Proxy setting for this network" or "Manual Proxy Configuration"
If choosing "Manual Proxy Configuration" Enter the IP address for the HTTP proxy server
Enter the port of the HTTP proxy server
Click Okay

Instructions for FireFox 2

Select the Tools Menu
Select Options
Select Connection Settings
Select Manual Proxy Configuration
Check Use the same proxy for all protocols
Enter the IP address for the HTTP proxy server
Enter the port of the HTTP proxy server
Click Okay

Instructions for Internet Explorer 6.0

On the Tools menu in Internet Explorer, click Internet Options, click the Connections tab, and then click LAN Settings.
Under Proxy server, click to select the Use a proxy server for your LAN check box.
In the Address box, type the IP address of the proxy server.
In the Port box, type the port number that is used by the proxy server for client connections (by default, 8080).
You can click to select the Bypass proxy server for local addresses check box if you do not want the proxy server computer to be used when you connect to a computer on the local network (this may speed up performance).
Click OK to close the LAN Settings dialog box.
Click OK again to close the Internet Options dialog box.

Opera

Select the Tools Menu
Select Preferences
Select Advanced Tab
Select Proxy Servers
Check the box next to HTTP
Enter the proxy server's IP address in the first box and the proxy's port in the box after "Port"
OK your way out

What is MAC Address ?

Tue, 31 Mar 2009 15:50:58 +0100

In computer networking, a Media Access Control address (MAC address), Ethernet Hardware Address (EHA), hardware address, adapter address or physical address is a quasi-unique identifier assigned to most network adapters or network interface cards (NICs) by the manufacturer for identification. If assigned by the manufacturer, a MAC address usually encodes the manufacturer's registered identification number.

Three numbering spaces, managed by the Institute of Electrical and Electronics Engineers (IEEE), are in common use for formulating a MAC address: MAC-48, EUI-48, and EUI-64. The IEEE claims trademarks on the names "EUI-48" and "EUI-64", where "EUI" stands for Extended Unique Identifier.

Although intended to be a permanent and globally unique identification, it is possible to change the MAC address on most of today's hardware, an action often referred to as MAC spoofing. Unlike IP address spoofing, where a sender spoofing their address in a request tricks the other party into sending the response elsewhere, in MAC address spoofing (which takes place only within a local area network), the response is received by the spoofing party.

A host cannot determine from the MAC address of another host whether that host is on the same OSI Layer 2 network segment as the sending host, or on a network segment bridged to that network segment.

In TCP/IP networks, the MAC address of a subnet interface can be queried with the IP address using the Address Resolution Protocol (ARP) for Internet Protocol Version 4 (IPv4) or the Neighbor Discovery Protocol (NDP) for IPv6. On broadcast networks, such as Ethernet, the MAC address uniquely identifies each node and allows frames to be marked for specific hosts. It thus forms the basis of most of the Link layer (OSI Layer 2) networking upon which upper layer protocols rely to produce complex, functioning networks.

How to change MAC Address ?

source: http://en.wikipedia.org/wiki/MAC_address

Finding the IP address of an email sender in GMail, Yahoo Mail, and Outlook

Mon, 30 Mar 2009 15:00:54 +0100

Finding the IP address of an email sender in GMail, Yahoo Mail, and Outlook

Let’s go ahead and take a look at how you would do this for Google, Yahoo and Outlook since those are the most popular email clients.

Google’s Gmail

1. Log into your account and open the email in question.

2. Click on the down arrow that’s to the right of the Reply link. Choose Show Original from the list.

Now here’s the technical part that I was telling you about earlier! You need to look for the lines of text that start with “Received: from“. It might be easier to simply press Cntrl + F and perform a search for that phase. You’ll notice that there are several Received From’s in the message header. This is because the message header contains the IP addresses of all of servers involved in routing that email to you.

To find the first computer that originally sent the email, you’ll have to find the Received From that’s farthest DOWN. As you can see from the above image, the first one is from a computer called “aseem” with the IP address 72.204.154.191. Then it was routed to my ISP’s server at eastrmmtao104.cox.net and so on and so forth till it got to your email server.

The computer aseem is my personal home computer and that’s my public IP address for my house! I’ll go through Yahoo and Outlook before talking about tracking the location of that IP address.

Yahoo Mail Beta

1. Log into your account and open the email (if you’re using Yahoo Mail Beta with the new preview interface, make sure you double-click on the email so that it opens in a new tab)

2. At the top right, you’ll see there is a drop-down option where Standard Header is selected by default.

3. Click on it and choose Full Header.

Again, you’ll see the same information as before, just in a different window:

Microsoft Outlook

1. Open the email in Outlook by double-clicking on it

2. Go to View at the top menu (the menu options for the email, not the main Outlook window) and choose Options.

You’ll get a dialog box where you can set the message options and at the bottom you’ll see the Internet Headers box. For some silly reason, the box is very small and you have to scroll a lot, so it’s best to simply copy and paste the text into Notepad to view it more easily.

Tracking the location of an IP address:

Now that we have our originating IP address of 72.204.154.191, let’s find out where that is! You can do this by perform a location lookup on the IP address. You can use IP lookup tool on myiptest.com

source: http://www.online-tech-tips.com

What is Dynamic DNS?

Wed, 25 Mar 2009 15:42:46 +0000

Dynamic DNS is a method, protocol, or network service that provides the capability for a networked device, such as a router or computer system using the Internet Protocol Suite, to notify a domain name server to change, in real time (ad-hoc) the active DNS configuration of its configured hostnames, addresses or other information stored in DNS.

A popular application of dynamic DNS is to provide a residential user's Internet gateway that has a variable, often changing, IP address with a well known hostname resolvable by network applications through standard DNS queries.

Dynamic DNS providers provide a software client program that automates the discovery and registration of client's public IP addresses. The client program is executed on a computer or device in the private network. It connects to the service provider's systems and causes those systems to link the discovered public IP address of the home network with a hostname in the domain name system. Depending on the provider, the hostname is registered within a domain owned by the provider or the customer's own domain name. These services can function by a number of mechanisms. Often they use an HTTP service request since even restrictive environments usually allow HTTP service. This group of services is commonly also referred to by the term Dynamic DNS, although it is not the standards-based DNS Update method. However, the latter might be involved in the providers systems.

Most home networking routers today have this feature already built into their firmware. One of the early routers to support Dynamic DNS was the UMAX UGate-3000 in 1999, which supported the TZO.COM dynamic DNS service.

An example of use is a home user who wishes to access a computer on a home network while travelling. The user may be supplied with a different IP address every time an Internet connection to the service provider is made, so there is no stable address to connect to. If a DDNS service is used to associate a fixed address to a device, then the user can, for example, establish a Virtual Private Network (VPN) to the network using that address. As a detailed example, the IP address can be 123.234.111.112 one day, 123.124.45.15 the next, but the DDNS address will always be, say, myhome.ddns.org. A remote control program such as VNC server can be left running on a machine in the network; the user can connect to the network by establishing a password-protected VPN to myhome.ddns.org, then connect to the machine using a VNC client program.

In Microsoft Windows networks, Dynamic DNS is an integral part of Active Directory, because domain controllers register their network service types in DNS so that other computers in the Domain (or Forest) can access them.

Increasing efforts to secure Internet communications today involve encryption of all dynamic updates via the public Internet, as these public dynamic DNS services have been abused increasingly to design security breaches. Standards-based methods within the DNSSEC protocol suite, such as TSIG, have been developed to secure DNS updates, but are not widely in use. Microsoft developed alternative technology (GSS-TSIG) based on Kerberos authentication.

source: http://en.wikipedia.org/wiki/Dynamic_DNS

What is SSH (Secure Shell) ?

Wed, 11 Mar 2009 10:06:00 +0000

Secure Shell or SSH is a network protocol that allows data to be exchanged using a secure channel between two networked devices. Used primarily on Linux and Unix based systems to access shell accounts, SSH was designed as a replacement for TELNET and other insecure remote shells, which send information, notably passwords, in plaintext, leaving them open for interception. The encryption used by SSH provides confidentiality and integrity of data over an insecure network, such as the Internet.

Definition

SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary.

SSH is typically used to log into a remote machine and execute commands, but it also supports tunneling, forwarding TCP ports and X11 connections; it can transfer files using the associated SFTP or SCP protocols. SSH uses the client-server model.

An SSH server, by default, listens on the standard TCP port 22.

An SSH client program is typically used for establishing connections to an SSH daemon accepting remote connections. Both are commonly present on most modern operating systems, including Mac OS X, Linux, FreeBSD, Solaris and OpenVMS. Proprietary, freeware and open source versions of various levels of complexity and completeness exist.

Uses of SSH

Example of tunneling an X11 application over SSH: the user 'josh' has SSHed from the local machine 'foofighter' to the remote machine 'tengwar' to run xeyes.

Logging into OpenWRT via SSH using PuTTY running on Windows.

Note that SSH is a protocol that can be used for many applications. Some of the applications below may require features that are only available or compatible with specific SSH clients or servers. For example, using the SSH protocol to implement a VPN is possible, but presently only with the OpenSSH server and client implementation.

* for login to a shell on a remote host (replacing Telnet and rlogin)

* for executing a single command on a remote host (replacing rsh)

* for copying files from a local server to a remote host. See SCP, as an alternative for rcp

* in combination with SFTP, as a secure alternative to FTP file transfer

* in combination with rsync to backup, copy and mirror files efficiently and securely

* for port forwarding or tunneling a port (not to be confused with a VPN which routes packets between different networks or bridges two broadcast domains into one.).

* for using as a full-fledged encrypted VPN. Note that only OpenSSH server and client supports this feature.

* for forwarding X11 through multiple hosts

* for browsing the web through an encrypted proxy connection with SSH clients that support the SOCKS protocol.

* for automated remote monitoring and management of servers

* for securely mounting a directory on a remote server as a filesystem on a local computer using SSHFS.

PuTTY SSH client: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

source: http://en.wikipedia.org/wiki/Secure_Shell

What is a Router?

Wed, 11 Mar 2009 09:41:44 +0000

A router is a device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. Routers are located at gateways, the places where two or more networks connect, and are the critical device that keeps data flowing between networks and keeps the networks connected to the Internet. When data is sent between locations on one network or from one network to a second network the data is always seen and directed to the correct location by the router. They accomplish his by using headers and forwarding tables to determine the best path for forwarding the data packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.

The Internet itself is a global network connecting millions of computers and smaller networks — so you can see how crucial the role of a router is to our way of communicating and computing.

Why Would I Need a Router?

For most home users, they may want to set-up a LAN (local Area Network) or WLAN (wireless LAN) and connect all computers to the Internet without having to pay a full broadband subscription service to their ISP for each computer on the network. In many instances, an ISP will allow you to use a router and connect multiple computers to a single Internet connection and pay a nominal fee for each additional computer sharing the connection. This is when home users will want to look at smaller routers, often called broadband routers that enable two or more computers to share an Internet connection. Within a business or organization, you may need to connect multiple computers to the Internet, but also want to connect multiple private networks — and these are the types of functions a router is designed for.

Routers for Home & Small Business

Not all routers are created equal since their job will differ slightly from network to network. Additionally, you may look at a piece of hardware and not even realize it is a router. What defines a router is not its shape, color, size or manufacturer, but its job function of routing data packets between computers. A cable modem which routes data between your PC and your ISP can be considered a router. In its most basic form, a router could simply be one of two computers running the Windows 98 (or higher) operating system connected together using ICS (Internet Connection Sharing). In this scenario, the computer that is connected to the Internet is acting as the router for the second computer to obtain its Internet connection.

Going a step up from ICS, we have a category of hardware routers that are used to perform the same basic task as ICS, albeit with more features and functions. Often called broadband or Internet connection sharing routers, these routers allow you to share one Internet connection between multiple computers.

source: http://www.webopedia.com

What is PPP and PPPoE?

Wed, 11 Mar 2009 09:37:15 +0000

PPP over Ethernet (PPPoE) provides the ability to connect a network of hosts over a simple bridging access device to a remote Access Concentrator. With this model, each host utilizes it's own PPP stack and the user is presented with a familiar user interface. Access control, billing and type of service can be done on a per-user, rather than a per-site, basis.

To provide a point-to-point connection over Ethernet, each PPP session must learn the Ethernet address of the remote peer, as well as establish a unique session identifier. PPPoE includes a discovery protocol that provides this.

PPPoE has two distinct stages. There is a Discovery stage and a PPP Session stage. When a Host wishes too initiate a PPPoE session, it must first perform Discovery to identify the Ethernet MAC address of the peer and establish a PPPoE SESSION_ID. While PPP defines a peer-to-peer relationship, Discovery is inherently a client-server relationship. In the Discovery process, a Host (the client) discovers an Access Concentrator (the server). Based on the network topology, there may be more than one Access Concentrator that the Host can communicate with. The Discovery stage allows the Host to discover all Access Concentrators and then select one. When Discovery completes successfully, both the Host and the selected Access Concentrator have the information they will use to build their point-to-point connection over Ethernet. The Discovery stage remains stateless until a PPP session is established. Once a PPP session is established, both the Host and the Access Concentrator MUST allocate the resources for a PPP virtual interface.

source: http://www.javvin.com/protocolPPPoE.html

What is LAN (Local Area Network)?

Wed, 25 Feb 2009 16:30:03 +0000

A local area network (LAN) consists of two or more computers connected together in a building or home using software and hardware. A LAN is contrasted to a wide area network (WAN) such as the Internet, which covers a large geographic area. In a LAN, there is a main computer or server, and remote computers called clients. By creating a LAN in the home or office, computers on the LAN can share files, resources, and if desired, an Internet connection.

A LAN can be one of two types: wired or wireless. A wired LAN requires Ethernet cable to physically connect all computers on the network to a main device called a switch. A wireless LAN uses radio waves to communicate, eliminating the need for wires. Therefore, the hardware used in a LAN should all be of either the wireless or wired type.

A LAN is fairly easy to setup. All Microsoft operating systems since Windows 98 Special Edition (SE) have included built-in networking software. In terms of hardware, each computer requires a network interface card (NIC). A switch is also required. This is a device that resembles an external modem and directs information on the network. If the LAN will be talking to another network, like the Internet, a router is also required. Luckily, one can purchase an external DSL modem with a built-in switch and router, in wireless or wired configurations.

Desktop computers typically use internal NICs that slip into an available slot on the motherboard, while a laptop might use a portable computer (PC) NIC. This type of NIC resembles a thick credit card that can be inserted into the PC card slot on the laptop.

If the LAN is to be hard-wired, each NIC must have an Ethernet port for connecting an Ethernet cable. In a wireless LAN, each NIC might feature a small radio wave antenna. The server is hard-wired to the DSL modem, switch or router, while the clients can communicate wirelessly, if desired. If there is to be no connection to the Internet or any other LAN or WAN, a switch alone will be fine.

Once the LAN has been set up, an administrator can designate which files and programs can be shared on the LAN. Some areas of the server may be kept behind a firewall to prevent access. All traffic on the LAN, including email, Internet surfing and other activities, can be monitored by the administrator using various tools.

The advantages of a LAN in the office are manifold. By having a central printer, for example, a business can avoid buying individual printers for each workstation. Workflow is enhanced while being easier than ever to control and administer. Flexibility and creativity can also improve. A LAN is a win-win situation for management and employees alike.

A LAN at home is extremely convenient. Share programs, images, music and digital projects, and enjoy gaming. Share a high-end color printer, scanner or other equipment. If concerned about your children’s Internet use, a LAN is one way to supervise online activity.

A hard-wired LAN is more trouble to install, as it requires running a physical Ethernet cable from each client to the DSL, switch or router. However, a wired LAN is reliable and secure. A wireless LAN is easier to install and less expensive, but requires a few more steps in the software setup to ensure it is secure. It may also be slower than a wired LAN, but this depends on the wireless standard used, as newer standards effectively compete with Ethernet speeds.

source: http://www.wisegeek.com/what-is-a-lan.htm

What is Wireless access point?

Fri, 20 Feb 2009 09:44:45 +0000

In computer networking, a wireless access point (WAP or AP) is a device that allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth or related standards. The WAP usually connects to a wired network, and can relay data between the wireless devices (such as computers or printers) and wired devices on the network.

Introduction

Prior to wireless networks, setting up a computer network in a business, home, or school often required running many cables through walls and ceilings in order to deliver network access to all of the network-enabled devices in the building. With the advent of the Wireless Access Point, network users are now able to add devices that access the network with few or no new cables. Today's WAPs are built to support a standard for sending and receiving data using radio frequencies rather than cabling. Those standards, and the frequencies they use are defined by the IEEE. Most WAPs use IEEE 802.11 standards.

Common WAP Applications

A typical corporate use involves attaching several WAPs to a wired network and then providing wireless access to the office LAN. Within the range of the WAPs, the wireless end user has a full network connection with the benefit of mobility. In this instance, the WAP functions as a gateway for clients to access the wired network.

A Hot Spot is a common public application of WAPs, where wireless clients can connect to the Internet without regard for the particular networks to which they have attached for the moment. The concept has become common in large cities, where a combination of coffeehouses, libraries, as well as privately owned open access points, allow clients to stay more or less continuously connected to the Internet, while moving around. A collection of connected Hot Spots can be referred to as a lily-pad network.

The majority of WAPs are used in Home wireless networks.[citation needed] Home networks generally have only one WAP to connect all the computers in a home. Most are wireless routers, meaning converged devices that include a WAP, router, and often an ethernet switch in the same device. Many also converge a broadband modem. In places where most homes have their own WAP within range of the neighbors' WAP, it's possible for technically savvy people to turn off their encryption and set up a wireless community network, creating an intra-city communication network without the need of wired networks.

A WAP may also act as the network's arbitrator, negotiating when each nearby client device can transmit. However, the vast majority of currently installed IEEE 802.11 networks do not implement this, using a distributed pseudo-random algorithm called CSMA/CD instead.

source: http://en.wikipedia.org/wiki/Wireless_access_point

What is Port forwarding?

Thu, 19 Feb 2009 14:27:32 +0000

Port forwarding, sometimes referred to as port mapping, is the act of forwarding a network port from one network node to another. This technique can allow an external user to reach a port on a private IP address (inside a LAN) from the outside via a NAT-enabled router.

Purposes

Port forwarding allows remote computers (e.g. public machines on the Internet) to connect to a specific computer within a private LAN.[3]

For example:

    * forwarding port 80 to run an HTTP webserver within private LAN from internet
    * forwarding port 22 to allow Secure Shell access within private LAN from internet
    * forwarding port 21 to allow FTP access within private LAN from internet

Modern Linux machines achieve this by adding iptables rules to the nat table: with target DNAT to the PREROUTING chain, and/or with target SNAT in the POSTROUTING chain.BSD and Mac OS X machines use a similar tool named ipfw. The ipfw tool is likely already running as a built-in part of the operating system's kernel.

Some common caveats with port forwarding include:

* The need to forward the packets that come to the router's forwarded port as well as the need to rewrite them so that the machine to which the port is forwarded can reply to the original source address, which in turn leads to the inability of the destination (private) machine to see the actual originator of the forwarded packets, and instead see them as if originating from the router

* Only one networked machine can use a specific forwarded port at one time

* Traditional port forwarding allows the entire world access to the forwarded port, slightly reducing network security

Reverse port forwarding

Reverse port forwarding, or reverse port tunnelling, is done by two components, usually software-based, where one component acts as a session-server - listening on a session-port, while the other component acts as a session-client to the session-server component - connecting to the session-server. After a session is established, the session-server will often listen on (accept connections on) a port that is to be forwarded, and when a connection is made to this port, the connection traffic will be forwarded to the session-client (through the session-connection that was previously initiated by the session-client), usually with a destination of the session-client machine or another machine accessible from the session-client. A common situation where this type of forwarding is used is where a port needs to be accessed that is on a machine located behind a gateway/router or firewall that is not configurable by those wanting to access that port. This functionality is built-in to some implementations of SSH (Secure Shell), and there are also software systems available that are designed more specifically for this type of forwarding.

What is a static IP address/dynamic IP address?

Tue, 17 Feb 2009 09:28:00 +0000

A static IP address is a number (in the form of a dotted quad) that is assigned to a computer by an Internet service provider (ISP) to be its permanent address on the Internet. Computers use IP addresses to locate and talk to each other on the Internet, much the same way people use phone numbers to locate and talk to one another on the telephone. When you want to visit whatis.com, your computer asks a domain name system (DNS) server (think telephone information operator) for the correct dotted quad number (think phone number) for whatis.com and your computer uses the answer it receives to connect to the whatis.com server.

It would be simple if every computer that connects to the Internet could have its own static IP number, but when the Internet was first conceived, the architects didn't foresee the need for an unlimited number of IP addresses. Consequently, there are not enough IP numbers to go around. To get around that problem, many Internet service providers limit the number of static IP addresses they allocate, and economize on the remaining number of IP addresses they possess by temporarily assigning an IP address to a requesting Dynamic Host Configuration Protocol (DHCP) computer from a pool of IP addresses. The temporary IP address is called a dynamic IP address.

Requesting DHCP computers receive a dynamic IP address (think temporary phone number) for the duration of that Internet session or for some other specified amount of time. Once the user disconnects from the Internet, their dynamic IP address goes back into the IP address pool so it can be assigned to another user. Even if the user reconnects immediately, odds are they will not be assigned the same IP address from the pool. To keep our telephone telephone analogy going, using a dynamic IP address is similar to using a pay phone. Unless there is a reason to receive a call, the user does not care what number he or she is calling from.

There are times, however, when users who connect to the Internet using dynamic IP wish to allow other computers to locate them. Perhaps they want to use CU-SeeMe or use a VoIP application to make long distance phone calls using their IP connection. In that case, they would need a static IP address. The user has two choices; they can contact their ISP and request a static IP address, or they can use a dynamic DNS service. Either choice will probably involve an additional monthly fee.

Using a dynamic DNS service works as if there was an old-fashioned telephone message service at your computer's disposal. When a user registers with a DNS service and connects to the Internet with a dynamic IP address, the user's computer contacts the DNS service and lets them know what IP address it has been assigned from the pool; the service works with the DNS server to forward the correct address to the requesting DHCP computer. (Think of calling the message service and saying "Hi. I can be reached at 435.44.32.111 right now. Please tell anyone who tries to reach me to call that number.) Using a dynamic DNS service to arrange for computers to find you even though you are using a dynamic IP address is the next-best thing to having a static IP.

IPv6, which has also been called "IPng" (IP Next Generation), lengthens IP addresses from 32 bits to 128 bits and increasesthe number of available IP addressess significantly, making static IP addresses easier and less expensive to obtain and maintain.

What is an ISP (Internet Service Provider)?

Tue, 17 Feb 2009 09:21:31 +0000

An ISP (Internet Service Provider) is an organization that provides Internet access to others. Most of the time the term "ISP" refers to companies that provide Internet access to home users, although a company that provides Internet access to other companies can also be called an ISP, and not all ISPs are for-profit corporations.

But who is my ISP?

Your ISP is the company you pay for Internet access. If you have high-speed access such as cable modem or DSL, then your ISP is probably your cable company or phone company, although there are other companies that offer these services too (notably Earthlink). If you have old-fashioned, slow "dialup" access, you could be with AOL, Earthlink or any number of smaller ISPs.

If you are the person who pays the bills in your house, you'll already know. If not, just ask that person.

Using DNS Block Lists (DNSBLs)

Tue, 17 Feb 2009 08:49:56 +0000

Exim DNSBL Support

Exim has supported RBL from version 1.80, although the flexibility was increased (with a related change configuration options) on the release of Exim 3.00. With the release of Exim 4.00 the whole basis of policy checks on incoming mail changed to be based on a set of Access Control Lists (ACLs) applied at various during the incoming mail transaction. For this reason the configuration of Exim 4.x and later to use DNSBLs is complete different to that used for earlier versions.

Exim 4.x DNSBL Usage

In Exim 4.x a DNSBL lookup can be used in any of the incoming SMTP ACLs. However it is typical for the lookups to be used in the ACL handling RCPT TO - this allows policies to accept mail for postmaster or other special local parts (for example so a blocked sender can talk to the local postmaster about getting blocks lifted or excluded)

Exim 4.x example:

deny dnslists = dnsbl.sorbs.net : bl.spamcop.net : cbl.abuseat.org message = $sender_host_address is blacklisted in $dnslist_domain ${if def:dnslist_text { ($dnslist_text)}}

source: http://www.exim.org/howto/rbl.html

Sendmail Configuration

This page describes how configure sendmail 8.11.6 to block spam using a number of effective spam signature detection methods

First apply this patch to the source. If for some strange reason you choose not to implement any of the anti-spam rules in the .mc file this patch should be harmless.

Then ensure that your sendmail executable is compiled with MAP_REGEX defined. One way to do this is to include the line

Add these rules to the end of your .mc file, build a new .cf file with it, install, and restart sendmail to make all of the changes take effect. Don't forget to include your favorite external blacklists. Mine are:

FEATURE(`dnsbl', `zen.spamhaus.org', `"550 Mail from " $`'&{client_addr} " refused - see http://www.spamhaus.org/"')
FEATURE(`dnsbl', `dul.dnsbl.sorbs.net', `"550 Mail from " $`'&{client_addr} " refused - see http://www.dul.dnsbl.sorbs.net/"')
FEATURE(`dnsbl', `bl.spamcop.net', `"450 Mail from " $`'&{client_addr} " refused - see http://spamcop.net/bl.shtml"')

source: http://www.sdsc.edu/~jeff/spam/Sendmail.html

How do I change my IP address?

Mon, 16 Feb 2009 14:41:09 +0000

Additional information: Users often want to change their IP address because of one or more of the below reasons.

1. Network confliction or other network related issue.

2. Network application requires specific IP address or IP range.

3. Trying to protect themselves from other users.

4. Trying to deceive a vicious software program, user, or company.

Before reading any of the below information, you need to be aware of some network basics.

1. Know the difference between a static IP address and a dynamic IP address. See each of the links for additional information about each of these terms.

2. When on the Internet, it is up to your Internet Service Provider (ISP) to assign and give you your network address seen by the Internet. Additional details posted below.

3. If you're planning on designating and/or using a static IP address, you should be aware of how IP address ranges are handled and netmasks. See each of these links for additional information.

Modem users

When connecting to the Internet, your ISP will assign your computer an address each time you connect. This means that often each time you connect you'll have a different IP address. If you're wanting to change your IP address, try disconnecting and reconnecting.

Broadband users

Almost all broadband service providers will assign your computer or home network a static IP address. If you're connected to a broadband network and need to change your IP address we suggest contacting your broadband provider.

Changing your home network IP address

Microsoft Windows users

To change or specify the IP address of your computer for your own local area network (LAN), follow the below steps. Keep in mind that if you're connecting to the Internet with a broadband connection, adjusting your network settings may cause issues with your broadband connection. Finally, if your home network is setup through a network router, that router could be assigning your computer dynamic IP addresses, and specifying a static IP address may cause issues.

1. Get to the Microsoft Windows desktop.
2. Right-click on My Network Places or Network Neighborhood and click Properties.
3. Right-click on Local Area Connection and click Properties.
4. Click Internet Protocol (TCP/IP) and click Properties. If this is not present, you'll need to install this protocol.
5. In the Internet Protocol (TCP/IP) Properties window, select "Use the following IP address" if not already selected and specify the new IP address you wish to use. While entering this data you'll also need to specify the subnet mask and default gateway.

Linux users

The below information is for how to specify and adjust your network settings through the command prompt. Changing your network settings will require root access.

1. Get to the command prompt.

2. Move to the /etc/sysconfig/network directory.

3. Edit the interfaces file and adjust your network settings in this file.

source: computerhope.com

What is DNS Blacklist (DNSBL) ?

Thu, 12 Feb 2009 10:15:43 +0000

A DNS Blacklist, or DNSBL, is a means by which an Internet site may publish a list of IP addresses that some people may want to avoid and in a format which can be easily queried by computer programs on the Internet. The technology is built on top of the Internet Domain Name System, or DNS. DNSBLs are chiefly used to publish lists of addresses linked to spamming. Most mail transport agent (mail server) software can be configured to reject or flag messages which have been sent from a site listed on one or more such lists.

DNSBL names a medium, not any specific list or policy. There has been a good deal of controversy over the past several years over the operation of specific lists, such as the MAPS RBL and SPEWS.

Terminology

RBL is an abbreviation for "Real-time Blackhole List". As mentioned below, "RBL" was the name of the first system to use this technology, a proprietary MAPS DNSBL, and "RBL" is a registered trademark. Some pieces of mail software have configuration parameters that use "RBLs" or "RBL domains" when any DNSBLs can be used, not just the MAPS RBL.

DNSBL is an abbreviation that sometimes stands for "DNS blacklist", although different DNSBL operators define the term in various ways. The use of the word "blacklist" is somewhat controversial. The reasons cited include its association with Joseph McCarthy and legal liability. Instead, some people have suggested that DNSBL should stand for "DNS blocklist" even though DNSBLs are not always used for direct blocking, or "DNS blackhole list" based on the RBL expansion, even though the DNSBL method does not create true blackholes. A minimally controversial expansion of the acronym is "DNS-Based List".

DNSWL is an abbreviation for "DNS whitelist". It is a list of IP addresses that some people may want to treat more favourably.

RHSBL is an abbreviation for "Right Hand Side Blacklist". This is similar to a DNSBL but it lists domain names rather than IP addresses. The term comes from the "right-hand side" of an email address — the part after the @ sign — which clients look up in the RHSBL.

URIBL is an abbreviation for "Uniform Resource Identifier Blacklist". A URIBL lists domain names and IP addresses that appear in URIs such as web sites mentioned in message bodies. It contrasts with an RHSBL which lists domain names used in e-mail addresses.

source: http://en.wikipedia.org/wiki/DNSBL

What is Virtual Private Network (VPN) ?

Thu, 12 Feb 2009 09:49:36 +0000

VPN is an acronym for Virtual Private Network. A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) as opposed to running across a single private network.

The link-layer protocols of the virtual network are said to be tunneled through the larger network. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.

VPN service providers may offer best-effort performance, or may have a defined service level agreement (SLA) with their VPN customers. Generally, a VPN has a topology more complex than point-to-point.

A VPN allows computer users to access a network via an IP address other than the one that actually connects their computer to the Internet.

What is Traceroute ?

Tue, 27 Jan 2009 12:52:50 +0000

Tracerout is a utility that records the route (the specific gateway computers at each hop) through the Internet between your computer and a specified destination computer. It also calculates and displays the amount of time each hop took. Traceroute is a handy tool both for understanding where problems are in the Internet network and for getting a detailed sense of the Internet itself. Another utility, ping, is often used prior to using traceroute to see whether a host is present on the network.

The traceroute utility comes included with a number of operating systems, including Windows and Unix-based operating systems (such as IBM's AIX/6000) or as part of a TCP/IP package.

How It Works

When you enter the traceroute command, the utility initiates the sending of a packet (using the Internet Control Message Protocol or ICMP), including in the packet a time limit value (known as the "time to live" (TTL) that is designed to be exceeded by the first routerthat receives it, which will return a Time Exceeded message. This enables traceroute to determine the time required for the hop to the first router. Increasing the time limit value, it resends the packet so that it will reach the second router in the path to the destination, which returns another Time Exceeded message, and so forth. Traceroute determines when the packet has reached the destination by including a port number that is outside the normal range. When it's received, a Port Unreachable message is returned, enabling traceroute to measure the time length of the final hop. As the tracerouting progresses, the records are displayed for you hop by hop. Actually, each hop is measured three times. (If you see an asterisk (*), this indicates a hop that exceeded some limit.)

If you have a Windows operating system, try traceroute out by clicking on

Start-->Programs-->MS-DOS Prompt, and then at the C:WINDOWS prompt, enter: tracert www.myiptest.com

or whatever domain name for a destination host computer you want to enter. You can also enter the equivalent numeric form of the

What is Ping ?

Tue, 27 Jan 2009 12:02:46 +0000

Ping is a basic Internet program that allows a user to verify that a particular IP address exists and can accept requests. The verb ping means the act of using the ping utility or command. Ping is used diagnostically to ensure that a host computer you are trying to reach is actually operating. If, for example, a user can't ping a host, then the user will be unable to use the File Transfer Protocol (FTP) to send files to that host. Ping can also be used with a host that is operating to see how long it takes to get a response back. Using ping, you can learn the number form of the IP address from the symbolic domain name (see "Tip").

Loosely, ping means "to get the attention of" or "to check for the presence of" another party online. Ping operates by sending a packet to a designated address and waiting for a response. The computer acronym (for Packet Internet or Inter-Network Groper) was contrived to match the submariners' term for the sound of a returned sonar pulse.

Ping can also refer to the process of sending a message to all the members of a mailing list requesting an ACK (acknowledgement code). This is done before sending e-mail in order to confirm that all of the addresses are reachable.