EtherApe is a GNOME/pcap-based etherman, interman, and "tcpman" clone. It displays network activity graphically. Active hosts are shown as circles of varying size, and traffic among them is shown as lines of varying width. It supports Ethernet, FDDI, Token Ring, ISDN, PPP, WLAN, and SLIP transports. It knows about VLANs, IP, IPv6, TCP, UDP, FTP, and a number of other protocols. Additional statistics windows will let you concentrate on protocols or nodes.
ZABBIX is an enterprise-class distributed monitoring solution designed to monitor and track performance and availability of network servers, devices, and other IT resources. It supports distributed and Web-based monitoring, auto-discovery, real-time monitoring, SLA assurance, trending, and more.
di is a disk information utility that displays everything that df does and more. It features the ability to display your disk usage in whatever format you prefer. It also checks the user and group quotas, so that the user sees the space available for their use, not the system wide disk space. It is designed to be highly portable across many platforms and is great for heterogenous networks.
Pandora is a distributed system to monitor processes, performance, status, application, or operating parameters of almost any operating system. It has a decentralized management system, based on flexible user profiles, that allows the user to generate graphical reports, define alarms, and a full incident management system to operate a 24x7 monitoring team.
WIST is a PHP Web Interface that permits you to connect on a remote host/port and listen/filter a SIP dialog of a specific SIP From number, avoiding listening to all captured traffic pushed by siptraced. The stop control is via the browser's stop button. The output is colorized, and the "Call-ID" tag is highlighted to make it easy to locate.