Spider A program that gets it's name because it automatically walks the web and visits websites. They are commonly used to automatically visit search engines and directories submission pages and register customer websites for Internet marketing companies. They are also used by search engines and directories to visit websites and index the information found there. Sometimes called agents, indexing agents, robots and bots. They can also be used to gather specific information from WebPages such as any email address's found there.
Spiders do no harm and are welcomed on most servers.
Spiders can also be restricted by network administrators so that they can not gather info from certain selected domains or websites. This protocol is similar to the old way of dialing up to another computers modem via phone lines, but you use the Internet instead. U Unix Unix is an operating system that was originally developed by Bell Laboratories around 1970. URL Uniform Resource Locator. Domain Virus A virus is a small executable program that attaches itself to other executable programs.