HTTP Time Protocol is a time synchronization tool that uses Web server responses (HTTP headers) instead of the NTP protocol. If you are behind a corporate firewall, NAT device, or proxy server, HTP will still be able to synchronize the time. For high precision time synchronization, use ntpd.
LFT (Layer Four Traceroute) is a sort of "traceroute" that often works much faster than the commonly-used Van Jacobson method and goes through many configurations of packet-filter based firewalls. More importantly, LFT implements numerous other features, including TCP, UDP, or ICMP-based traces, AS number lookups through several reliable sources, loose source routing, netblock name lookups, and more. LFT also distinguishes between layer-4 protocols, which make its statistics slightly more realistic, and gives a savvy user the ability to trace protocol routes, not just layer-3 hops.
BixData is a cluster management tool that includes monitoring and system administration features. It monitors services (HTTP, ping, POP3, SMTP), performance, and processes. It has a management console for VMWare and Xen that supports multiple virtual machine hosts and guests. It can create critical notifications and send email alerts for any system event (HTTP, ping, CPU, memory, SMART diagnostics, VM stats). A graphical desktop supports real-time dynamic graphs. The runtime agents and server components are lightweight and easy to set up and run.
Very Simple Network Monitor is a bash shell script CGI that monitors a number of services on a network. It currently checks for node-up, TCP service up, and UDP service up. A service or system can be put in maintenance status to avoid repetitive alarms. It is easy to customize, trigger alarms by email, or whatever you like (depends on nmap for TCP/UDP service checks). Installation is also simple. It generates HTML with all statuses, and for all services just in one view.
The LARTC-HOWTO describes many advanced ways of routing and shaping traffic. Using the HOWTO, you will be able to shape traffic in myriad ways, which will help you lower latency for interactive use when others are downloading or uploading. It will also teach you how to limit certain hosts/protocols' bandwidth usage. It also explains many aspects of routing using the 'ip' tool from the iproute2 suite.
dim_STAT is a performance analysis and monitoring tool for Solaris, Linux, Mac OS X, and other UNIX systems. Its main features are a Web-based interface, data storage in a MySQL database, several data views, interactive (Java) or static (PNG) graphs, real-time monitoring, multi-host monitoring, post analyzing, statistics integration, professional reporting with automated features, and more.
Network Query Tool (NQT) is a one-stop solution for getting information about a domain or IP address. Instead of manually using different Unix commands or visiting numerous Web sites to investigate a host, just load Network Query Tool and enter the hostname or IP. NQT does the rest. It supports a large number of TLDs and ccTLDs.
Sniff formats hex packets from the tcpdump program and converts them to ASCII to make them easier to read and understand. Its features include colored console output, CSV file saving, and fully customizable output. The program directly accepts all tcpdump options, including parsing from packet files.