Bandwidth Daemon   
http://www.grofsoft.com

Bandwidth Daemon is an advanced network bandwidth monitor program for Windows 2000/XP. Rather than counting the bandwidth from all packets, Bandwidth Daemon passes each packet through filters to determine if it should be counted. You may define your own filters, to monitor different types of traffic. A filter is a simple boolean expression. Bandwidth Daemon has a built in web server, and all administration is done through a web based interface. This means that it is accessible from anywhere. For example, you can install it on a gateway/router pc, and access it using a browser on your desktop pc. You can also add passwords for both guest and admin access. The default web page for Bandwidth Daemon provides an overview of recent usage for all your filters. You can configure the intervals you want to view. For example: Current Day, Current Month, Last 30 Days, Last 5 Minutes, etc. Bandwidth data is summarised into Minute, Hour, Daily, Weekly, and Monthly intervals. You can configure the length of data to store for each interval. The history database is optimised to minimise disk activity, while ensuring that no more than 1 minute of data will be lost in the event of a power failure. The database uses a transaction log, with two phase commit, to prevent corruption in the event of a power failure or system crash. Bandwidth Daemon runs as an NT service, so it will always be gathering packets, even when you are not logged in. It consumes minimal CPU and memory. The executable is around 200KB on Windows, and it typically consumes less than 2MB of memory.

TrafMeter   
http://lastbit.com

TrafMeter is a Windows-based tool providing realtime traffic accounting and monitoring. You can use it to count useful traffic of your computer (it's free!) or use to build the traffic accounting system for all PCs in your office LAN. It makes easy to count custom IP packets and troubleshooting problems saving your efforts as a network administrator. In TrafMeter, you can set unlimited number of filters for captured traffic, defining network packets which are used for tracking/reporting. It supports a creation of rulesets for various monitoring purposes. The rulesets can be used for single hosts, subnets, as well as specific groups of hosts - i.e. all hosts in/not in your LAN, specific IP protocols (ICMP,TCP,UDP,OSPF,etc). In addition, TrafMeter allows TCP/UDP port filtering. It includes real-time presentation of traffic activity via graphical charts. Each filter is represented by a unique color, which allows the webmaster and/or administrator to easily 'see' the Internet connection usage of individual users. TrafMeter supports a tracking of network packets for the different filters, letting you analyze and comment on the monitored traffic (which may include MAC addresses from Ethernet headers and the ToS field from IP headers). TrafMeter allows to track visited websites by its name using HTTP Host Header Logging. Report generation via XML, or to the more common database (Microsoft SQL Server, Oracle, MySQL) is present as well.

Winmail Mail Server   
http://www.magicwinmail.net

Winmail Server is an enterprise class mail server software system offering a robust feature set, including extensive security measures. Winmail Server supports SMTP, POP3, IMAP, Webmail, LDAP, multiple domains, SMTP authentication, spam protection, anti-virus protection, SSL/TLS security, Network Storage, remote access, Web-based administration, and a wide array of standard email options such as filtering, signatures, real-time monitoring, archiving, and public email folders. Flexibility Winmail Server adapts well to many different network environments, with support for the following options: Internet connection methods such as ADSL, ISDN, FTTB, cable modem and dial-up Webmail, either as virtual directory or web site, under IIS, Apache and PWS. Two types of email gateways: POP3 download and ETRN download, allowing access by multiple users to one email account without conflict. Automatic extraction and conversion of MS-TNEF (winmail.dat) attachments. Static and dynamic IP connections. Ease of Use Winmail Server supports the following user email functionality: Popular email client software products such as Outlook Express, Outlook, Netscape and Eudora.Configure Email Client Software Multi-language Webmail Anti-virus functions, including built-in API as well as support for most enterprise class anti-virus engines Anti-Virus Engines list SMS notification to send a mobile phone message upon arrival of new email Personal email signatures Email groups for efficient communication and collaboration between individual group members Email file attachment filtering by file names and type settings Email archiving Event calendar and user schedule functions IMAP (Internet Message Access Protocol) to access mail on server LDAP (Lightweight Directory Access Protocol) and IMAP public fold

MG-Shadow: Computer monitoring software   
http://www.mgwaycorp.com

The most stable and easy to use software to secretly monitor anyone's computer. MG-Shadow monitors and records programs and windows launched, all keystrokes and passwords typed, visited websites, sent or received emails, chats, instant messengers, screenshots and more. 100% invisible and light on computer resources. Tons of user-friendly features, such as advanced scheduler, websites blocker, remote email reporting, advanced stealth technology, powerful built-in screenshots viewer, encrypted log data. The licensed version comes with 6 powerful bonuses ($300 value), 90 days money back guarantee and free upgrades for life.

SiteMonNak   
http://www.nakware.com

SiteMonNak can monitor and report on the status of a variety of items that affect the accessibility of web sites including https web sites, items like DNS, Ping and HTTP response. What items you have monitored is very flexible. When a problem is detected you can be informed in a variety of different ways including emails, audio alerts, pop-up messages and executing programs (enabling rebooting failed servers etc). You can also set the number of times to verify a problem before being alerted. SiteMonNak keeps detailed logs of problems detected and when the problems are cleared. There are statistics kept for various aspects of site availability. SiteMonNak is designed to be an easy and efficient way to keep watch of your web site availability. This is an powerful tool for webmasters to keep their websites up.