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The Zipit Wireless Messenger is a small clamshell device originally produced by Aeronix, which is now under the spin-off Zipit Wireless, Inc., that enables Instant Messaging (AOL Instant Messenger, Yahoo! Messenger, MSN Messenger).

ZipIt is a Macintosh program that compresses and uncompresses files in the “zip format”. The zip format is popular on the IBM and on other platforms, such as Unix. You can tell if a file is in zip format simply by examining its name: if it ends in ‘.zip’, it is a zip file. (Note that if it ends in ‘.Z’ or ‘.gz’, it is NOT a zip file. The former belongs to a program called Compress, and the latter to a program called GZip.)

The zip format is most useful when compressing files destined for another computer platform, such as the IBM, or for uncompressing zip files received from other platforms. ZipIt can create zip archives intended solely for the Macintosh, but the zip format is not a standard compression format on the Mac.

Tags: Zipit, Zipit Wireless

In computer networking, MAC Filtering (or EUI filtering, or layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network.

MAC filter can filter each computer through MAC address in LAN; can also bind one MAC address with a static IP address. Following shows a [MAC Filter Config] dialog:

MAC addresses are uniquely assigned to each card, so using MAC filtering on a network permits and denies network access to specific devices through the use of blacklists and whitelists. While the restriction of network access through the use of lists is straightforward, an individual person is not identified by a MAC address, rather a device only, so an authorized person will need to have a whitelist entry for each device that he or she would use to access the network.

While giving a wireless network some additional protection, MAC Filtering can be circumvented by scanning a valid MAC (via airodump-ng) and then changing the own MAC into a validated one. This can be done in the Windows Registry or by using commandline tools on a Linux platform.

Tags: mac addresses, MAC filtering, wireless network

SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it is limited in its ability to queue messages at the receiving end, it is usually used with one of two other protocols, POP3 or IMAP, that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving e-mail. On Unix-based systems, sendmail is the most widely-used SMTP server for e-mail. A commercial package, Sendmail, includes a POP3 server. Microsoft Exchange includes an SMTP server and can also be set up to include POP3 support.

While electronic mail servers and other mail transfer agents use SMTP to send and receive mail messages, user-level client mail applications typically only use SMTP for sending messages to a mail server for relaying. For receiving messages, client applications usually use either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP) or a proprietary system (such as Microsoft Exchange or Lotus Notes/Domino) to access their mail box accounts on a mail server.

SMTP usually is implemented to operate over Internet port 25. An alternative to SMTP that is widely used in Europe is X.400. Many mail servers now support Extended Simple Mail Transfer Protocol (ESMTP), which allows multimedia files to be delivered as e-mail.

Tags: client mail, lotus notes domino, SMTP

Step 1: Click on the Orb (Windows 7 logo) then click Control panel.

Step 2: Click View network status and task under Network and Internet.

Step 3: Click Connect to a network.

Step 4: Select your wireless network name, check the box for Connect automatically, and click Connect.

Step 5: Type the network security or pre-share key for the network and click OK.

Tags: Windows 7, wireless network

WPA is a more powerful security technology for Wi-Fi networks than WEP. It provides strong data protection by using encryption as well as strong access controls and user authentication. WPA utilizes 128-bit encryption keys and dynamic session keys to ensure your wireless network’s privacy and enterprise security.

There are two basic forms of WPA:

• WPA Enterprise (requires a Radius server)
• WPA Personal (also known as WPA-PSK)

Either can use TKIP or AES for encryption. Not all WPA hardware supports AES.

WPA-PSK is basically an authentication mechanism in which users provide some form of credentials to verify that they should be allowed access to a network. This requires a single password entered into each WLAN node (Access Points, Wireless Routers, client adapters, bridges). As long as the passwords match, a client will be granted access to a WLAN.

Encryption mechanisms used for WPA and WPA-PSK are the same. The only difference between the two is in WPA-PSK, authentication is reduced to a simple common password, instead of user-specific credentials.

The Pre-Shared Key (PSK) mode of WPA is considered vulnerable to the same risks as any other shared password system – dictionary attacks for example. Another issue may be key management difficulties such as removing a user once access has been granted where the key is shared among multiple users, not likely in a home environment.

Tags: PSK, WPA, WPA-PSK