Options
Network Utilities
Traceroute
The Internet is a large and complex aggregation of network hardware, connected together by gateways. Tracking the route one’s packets follow (or finding the miscreant gateway that’s discarding your packets) can be difficult. Traceroute utilizes the IP protocol ‘time to live’ field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path to some host.
The only mandatory parameter is the destination host name or IP number. The default probe datagram length is 40 bytes, but this may be increased by specifying a packet size (in bytes) after the destination host name.
Netstat
The netstat command symbolically displays the contents of various network-related data structures. There are a number of output formats, depending on the options for the information presented. The first form of the command displays a list of active sockets for each protocol. The second form presents the contents of one of the other network data structures according to the option selected. Using the third form, with a wait interval specified, netstat will continuously display the information regarding packet traffic on the configured network interfaces. The fourth form displays statistics for the specified protocol or address family. The fifth form displays per interface statistics for the specified protocol or address family. The sixth form displays mbuf(9) statistics. The seventh form displays routing table for the specified address family. The eighth form displays routing statistics.
Whois
Internet domain name and network number directory service
The Whois utility looks up records in the databases maintained by several Network Information Centers (NICs).