SmartSniff allows you to capture TCP/IP packets that pass through your network adapter, and view the captured data as sequence of conversations between clients and servers. You can view the TCP/IP conversations in Ascii mode (for text-based protocols, like HTTP, SMTP, POP3 and FTP.) or as hex dump. (for non-text base protocols, like DNS)
System Requirements:

SmartSniff can capture TCP/IP packets on any 32-bit Windows operating system (Windows 98/ME/NT/2000/XP) as long as WinPcap capture driver is installed and works properly with your network adapter.
Under Windows 2000/XP (or greater), SmartSniff also allows you to capture TCP/IP packets without installing any capture driver, by using 'Raw Sockets' method. However, this capture method has some limitations and problems:

Outgoing UDP and ICMP packets are not captured.
On Windows XP SP1 outgoing packets are not captured at all - Thanks to Microsoft's bug that appeared in SP1 update... This bug was fixed on SP2 update, but under Vista, Microsoft returned back the outgoing packets bug of XP/SP1. On Windows Vista with SP1, only UDP packets are captured. TCP packets are not captured at all.

What's New in version 1.50:
Added 'Last Packet Time' column - Displays the date/time of the last packet received.
Added 'Data Speed' column - Displays the calculated speed of the TCP connection in KB per second.