Glossary

Administration Server. The HTTP server used to configure any Netscape 2.0 servers, such as iPlanet Web Proxy Server, installed on your machine.

Cache. A storage area that contains copies of original data stored locally so that the data doesn't have to be retrieved from a remote server each time it is requested.

Cache build. The creation of the cache hierarchy.

Cache capacity. How much data the cache can hold and still be efficient and effective. Cache capacity is related to the cache hierarchy in the cache directories. The larger the hierarchy, the bigger the capacity. The cache capacity should be configured to be equal to or greater than the cache size.

Cache directory hierarchy. The proxy's directory structure for storing cache files.

Cache Manager. A periodic clean-up process to remove old files to make room for new ones.

Cache Manager daemon. A process that monitors the cache size and spawns the Cache Manager when necessary.

Cache Monitor. A process daemon for determining the status of the cache directory structure.

Cache refresh. Replacing a cached document with a new copy from the content server.

Cache repair. A process to repair a cache damaged by a software failure, system crash, disk breakdown, or full file system.

Cache root. A directory on the proxy server machine that contains all cached files. The proxy controls which documents are copied to the cache root, and the Cache Manager daemon purges this directory structure to control the amount of data stored.

Cache partition. You can divide the cache into multiple directories or disk partitions.

Cache size. The total amount of disk space available for the proxy cache directory structure, which can be specified during initial proxy configuration and can later be changed through the online forms or the obj.conf configuration file. For efficiency, the cache size should not exceed the cache capacity.

Cache section. Section of the Netscape Proxy cache. The number of cache sections can be from 1 to 256, and must be a power of two (1, 2, 4, 8, 16, ..., 256). Each cache section can hold 100-250 megabytes of data; the optimum size is around 125 MB per section.

Cache up-to-date check. A check to determine if the copy in the cache is still valid, and if not, refresh it.

CERN. The European Laboratory for Particle Physics (CERN) invented the World Wide Web to share information among research groups. This is where the CERN proxy prototype was produced.

client. An individual user or the web browser they are using (such as Netscape Navigator).

Common logfile format. The format used by the server for entering information into the access logs. The format is the same among all of the major servers.

Content server. A server that contains the original documents that are requested by clients directly or through a proxy server.

DMZ. Demilitarized Zone. Taken from the military term for a safety zone between battle lines, this refers to an area within the firewall. Often this is a single machine with access to the internal site and the outside network. See also firewall.

DNS. Domain Name Service. The system used by machines on a network to associate standard IP addresses (such as 198.95.251.) with host names (such as www.netscape.com). Machines typically get this translated information from a DNS server, or look it up in tables maintained on their systems.

DNS alias. A host name that points to another host name—specifically a DNS CNAME record. Machines always have only one real name, but they can have more than one alias. For example, www.[yourdomain].[domain] might be an alias that points to a real machine called realthing.[yourdomain].[domain] where the server currently exists.

EMACS. A Unix text editor that can also be used to read email and news.

Expire. To label a document as "expired," or too old to serve to a client. The proxy will retrieve a current copy directly from the content server the next time a client requests the document. If the content server is unavailable, the expired document can still be served to the client with a message stating that it isn't current.

Expires header. A header that contains the expiration time of the returned document, as specified by the remote server.

Extended logfile format. Similar to the common logfile format, but it contains additional information.

File extension. The last section of a file name that typically defines the type of file (for example, .GIF and .HTML). For example, in the filename index.html the file extension is html.

File type. The format of a given file. For example, a graphics file doesn't have the same file type as a text file. File types are usually identified by the file extension (.GIF or .HTML).

Firewall. A network configuration, usually both hardware and software, that forms a fortress between networked computers within an organization and those outside the organization. It is commonly used to protect information such as a network's email and data files within a physical building or organization site. The area within the firewall is called the demilitarized zone, or DMZ. Often, a single machine in the DMZ is allowed access to both internal and external computers. The computer in the DMZ is directly interacting with the Internet, so strict security measures on it are required.

GIF. The Graphics Interchange Format A cross-platform image format originally created by CompuServe. GIF files are usually much smaller than other graphic file types (.BMP, .TIFF). GIF is one of the most common interchange formats. GIF images are readily viewable on Unix, Microsoft Windows, and Apple Macintosh systems.

Hard restart. Terminating the process, and starting it up again.

Host name. A name for a machine of the form machine.subdomain.domain, which is translated into an IP address. For example, www.netscape.com is the machine www in the subdomain netscape and com domain.

HTML. Hypertext Markup Language is a formatting language used for documents on the World Wide Web. HTML files are plain text files with formatting codes that tell browsers such as the Netscape Navigator how to display text, position graphics and form items, and display links to other pages.

HTTP. Hypertext Transfer Protocol is the method for exchanging information between HTTP servers and clients.

HTTPD. HTTP daemon, a program that serves information using the HTTP protocol. The iPlanet Communications Server is often called an httpd.

HTTPS. A secure version of HTTP, implemented using the secure sockets layer, SSL.

IANA. The Internet Assigned Numbers Authority, an organization that assigns port numbers to specific types of communications.

inittab. A file that lists programs that need to be restarted if they stop for any reason (this ensures a program continually runs). It is also called /etc/inittab because of its location. This isn't available on all Unix systems.

IP address. Internet Protocol address—a set of numbers, separated by dots, that specifies the actual location of a machine on the Internet.

Jail . A state in which a proxy's access is limited to a given directory. The chroot directive lets the Unix system administrator place a proxy server into a "jail" where it has access only to files in a given directory. This helps limit damage if the server's security is compromised because the intruder can access only the files in the one directory.

Last-modified header. The last modification time of the document file, returned in the HTTP response from the server.

MD5. A message digest algorithm by RSA Data Security, Inc., which can be used to produce a short digest of data of any size, and which has a high probability of being unique. It is mathematically extremely difficult to reproduce the same message digest.

MD5 signature. A message digest produced by the MD5 algorithm.

MIME. Multi-Purpose Internet Mail Extensions. This is an emerging standard for multimedia email and messaging.

NIS. Network Information Service—a system of programs and data files that Unix machines use to collect, collate, and share specific information about machines, users, file systems, and network parameters throughout a network of computers.

NCSA. The National Center for Supercomputing Applications is a research organization at the University of Illinois at Urbana-Champaign.

Password file. A file on Unix machines that stores Unix user login names, passwords, and user ID numbers. It is also known as /etc/passwd, because of where it is kept. The proxy also has its own password files for user authentication; these are not connected with Unix users.

pid. Process identification. The name of a process.

proxy. Server software, typically installed in the firewall DMZ, that allows access to the Internet across the firewall. A proxy is a special server that typically runs in conjunction with firewall software. The proxy server waits for a request from inside the firewall, forwards the request to the remote server outside the firewall, reads the response, then sends the response back to the client. iPlanet Web Proxy Server also provides caching of documents for improved performance, extensive logging, and fine-grain access control.

RAM. Random Access Memory. The physical semiconductor-based memory in a computer.

rc.local. A file that describes programs that are run when the machine starts. It is also called /etc/rc.local because of its location.

Redirection. A system by which clients accessing a particular URL are sent to a different location, either on the same server or on a different server. This is useful if a resource has moved and you want the clients to use the new location transparently. It's also used to maintain the integrity of relative links when directories are accessed without a trailing slash.

Regular expression. A form of expression that is used in Proxy for wildcard patterns for access control.

Resource. Any document (URL), directory, or program that the server can access and send to a client.

Root. The most privileged user available on Unix machines (also called superuser). The root user has complete access privileges to all files on the machine.

Section   . See cache section.

Server daemon. A process that, once running, listens for and accepts requests from clients.

Server root. A directory on the server machine dedicated to holding the server program, configuration, maintenance, and information files.

SOCKS. Firewall software that establishes a connection from inside a firewall to the outside when direct connection would otherwise be prevented by the firewall software or hardware (for example, the router configuration).

Soft restart. A process that causes the server to internally restart, that is, reread its configuration files, by sending the -HUP signal (signal number one) to the process. The process itself does not die (as it does in a hard restart).

SSL. Secure Sockets Layer. A software library establishing a secure connection between two parties (client and server) used to implement HTTPS, the secure version of HTTP.

Superuser. The most privileged user available on Unix machines (also called root). The superuser has complete access privileges to all files on the machine.

telnet. A protocol where two machines on the network are connected to each other and support terminal emulation for remote login.

Timeout. A specified time after which the server should give up trying to finish a service routine that appears hung.

top. A program on some Unix systems that shows the current state of system resource usage.

Top-level domain authority. The highest category of host name classification, usually signifying either the type of organization the domain is (.com is a company, .edu is an educational institution) or the country of its origin (.us is the United States, .jp is Japan, .au is Australia, .fi is Finland).

uid. User identification. A unique number associated with each Unix user on a machine.

URL. Uniform Resource Locator. The addressing system used by the server and the client to request documents. It is often called a location. The format of a URL is
[protocol]://[machine:port]/[document]

An example of a URL is http://www.netscape.com/index.html.

URL list. A list in the Netscape cache that contains all the URLs found in the cache, and links them to the cache files. This file can be browsed using the Cache Manager.

URL list repair. A process that repairs and updates a URL list that has been damaged by a software failure, a system crash, a disk breakdown, or a full file system.

white space. Any keystroke that leaves space on the screen, such as space bar, cursor return, line feed, horizontal tab, or vertical tab. In the obj.conf file, you can continue a directive line by adding white space at the beginning of the next line.

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