If you have budget constraint, you may like to try anti virus free software. I have been using AVG Free Anti-Virus software for years. It works really fine so far.

Anyway, if you are worry about technical support to the software you use, do consider fully supported commercial products from Trend Micro, Symantec, McAfee and so on.

Typically a network administrator will use Wireshark to troubleshoot network problems, the network security engineers use it to examine security problems, developers use it to debug protocol implementations and students may use it to learn network protocol internals.

Wireshark is able to inspect hundreds of protocols, with more being added all the time. It lets you interactively browse packet data from a live network or from a previously saved capture file. Packets captured are displayed with very detailed protocol information.

Wireshark’s native capture file format is libpcap format, which is also the format used by tcpdump and various other tools.

Like other protocol analyzers, Wireshark’s main window shows 3 views of a packet. It shows a summary line, briefly describing what the packet is. The second view is showing packet details which allows user to drill down to exact protocol or field. Finally, a hex dump shows the user exactly what the packet looks like when it goes over the wire. Coloring rules can be applied to the packet list for quick, intuitive analysis. Below is an example of Wireshark’s main window after packets have been captured.

Live data can be read from devices such as Ethernet, Token Ring, IEEE 802.11, PPP/HDLC, ATM, Bluetooth, USB, Frame Relay, FDDI, and others.

Wireshark is also having the decryption support for many protocols, including IPsec, ISAKMP, Kerberos, SNMPv3, SSL/TLS, WEP, and WPA/WPA2.

The output of Wireshark can be exported to XML, PostScript, CSV, or plain text.

Wireshark is available in all major modern operating systems like Windows, Linux, OS X, Solaris, FreeBSD, NetBSD, and many others. Installation process for Wireshark is fairly simple. For Windows system, you will need to install WinPcap capture driver (it is built into the Wireshark installation package) together with Wireshark as packet capturing in Wireshark is performed with the pcap library. WinPcap interacts with Windows OS to capture raw packet data, apply filters, and switch the network interface in and out of promiscuous mode.

You may download Wireshark from the official Wireshark web page.

Like TrueCrypt, you can create virtual disks on your PC/PDA using this tool. The virtual disk is encrypted using AES, Blowfish and other cyphers. However, it operates exactly like a normal disk – any data written to it is securely encrypted before being stored on your computer’s hard drive.

On a PC, the theoretical maximum volume size you can create for FreeOTFE virtual disk is 2^64 bytes (16777216 TB; 17179869184 GB). But bear in mind that FAT/FAT32 file system cannot support files larger than (4GB – 1 byte).

You may also use FreeOTFE to mount a volume file located on a network server. Security is also take care in this case – all data read/written to that volume will be sent over the network in encrypted form.

Like TrueCrypt, you do not need to install it. This is ideal for use on a USB stick. The best thing about FreeOTFE is the source code is available for free. Last but not least, be careful, never forget the password you use to create volume in this freeware. If you lost it, you are not able to get your data back!

By the way, you may download this excellent tool at it’s homepage.

Details for each of these three freeware will be introduced in the near future. Anyway, basically

1. Wireshark is a network protocol analyzer which was formerly called Ethereal. This is a very powerful tool use in capturing packets on the network.
2. NMap is a port scanner tool for Windows. You may use NMap in testing the range of ports open on a particular network device and subsequently know if any vulnerability is associated with it.
3. Eraser is use to securely delete files from your hard disk. It will completely remove data from your hard drive by overwriting the drive several times with selected pattern strings.

Wireshark and Nmap are mostly use in network system trouble shooting. These two security tools also popularly used in education institution to show students on how the network work. Eraser is mostly use in protecting the security of information in your personal computer.

The best feature that I found with TrueCrypt is it can create a virtual encrypted disk within a file and mounts it as a real disk. Files that is stored in this encrypted disk are automatically encrypted or decrypted on-the-fly and transparent to user.

TrueCrypt can also encrypts an entire partition or storage device such as USB flash drive or hard drive.

The other feature that I never try with TrueCrypt is the Encryption of a partition or drive where Windows is installed (pre-boot authentication).

No data stored on an TrueCrypt encrypted volume can be read (decrypted) without having the correct password or correct encryption key. Until decrypted, a TrueCrypt volume appears to be nothing more than a series of random numbers.

The encryption algorithms supported by TrueCrypt includes AES-256, Serpent, and Twofish. Additionally, five different combination of cascaded algorithms are available: AES-Twofish, AES-Twofish-Serpent, Serpent-AES, Serpent-Twofish-AES and Twofish-Serpent. The cryptographic hash functions used by TrueCrypt are RIPEMD-160, SHA-512, and Whirlpool.

From information security point of view, it is a good practice to protect your sensitive data with encryption software. TrueCrypt offers this excellent function to us freely!