If you are unable to resolve the problem, then please refer to our support website, at http://support.zeus.com, which provides an extensive FAQ, a range of product documentation, and access to our external mailing lists.
If this does not answer your question, use the Administration Server support form, described in Zeus Web Server User Guide. Alternatively contact the Zeus support team using the form at http://www.zeus.com/support/form/form.html.
Glossary
Access control Access control is a way of specifying who can access resources such as directories and files, and what access they can have. When a Virtual Server receives a request it applies the specified access rules to determine whether access will be granted. You can allow or deny access to specified enti- ties and users.
Access rule You can control access to a web site by building up a set of access rules. Each rule either allows or denies access to specified users and directories.
Address See Web Site Address Admin Server port
The Admin Server port is the port that you use to access the Zeus Web Server user interface. It is reported to you when you install Zeus Web Server. By default it is set to 9090. See also control port and port number.
Alias Aliases are a way of specifying “alternative web site
addresses” for a web site: the user goes to the same web site,
and sees the same web pages, whichever alias is used. It can be helpful to specify a number of alternative addresses that you think users might use to access your web site.
An aliased subdirectory is a directory that is configured to pass all requests for it to a specified directory or application. Back-end machines
receive and respond to requests from the front-end
machines.
Bandwidth throttling
Bandwidth throttling enables you to limit the bandwidth available to any given web site. It can be used to ensure that no single web site uses all the available bandwidth, compro- mising the availability of other web sites hosted by the same web server.
Certificate A string of data that when decoded, contains structured information. This may specify the name of a server, or infor- mation about a user. Certificates have checksums so that the data cannot be changed once it is encoded, and they can be self-signed or signed by another body, usually called a Certif- icate Authority. This allows programs to check that the data has been validated by one or more third parties.
CGI Script A program that is called using the CGI interface and runs to produce some output that is returned to the Virtual Server to return to the web browser.
Cluster A cluster is a group of web server components running on different machines. They are configured to provide the same web services and requests can be distributed as appropriate between machines in the cluster. They act together as one logical unit, and can be managed as a single entity. For example, a server farm might include a cluster of POP3 serv- ers and a cluster of web servers.
Control port The control port is the port that the web server component uses to communicate with its Administration Server. By default it is set to 9080. When a web server is installed at the same time as the Administration server, this information is shared automatically. See also Admin Server port and port
number.
Cookie A cookie is a small piece of text that the Virtual Server sends to the user’s browser (if configured to do so), and that the user’s browser then returns in every subsequent request. This
enables the Virtual Server to track the activity of each user accurately.
Directory indexing
Directory indexing specifies whether the web server returns a directory listing if it doesn’t find any of the configured index files in a directory.
Directory Mapping
Directory mapping is a way of specifying additional docu- ment root directories outside the web site document root. This means that you can enable someone to manage the con- tent of a particular directory without giving them access to the document root directory. You can also use directory mapping to put scripts in a separate directory, which you can then carefully control access to. To set directory mapping, you specify the URL prefix that users will use to access the specified directory, and the actual path to the directory. DNS The Domain Name System is a distributed hierarchical system
that associates IP addresses with host names, and vice versa. DNS Lookup DNS Lookup is the process of resolving IP addresses to host
names (and vice versa) using DNS.
Document root The document root (docroot) is the top-level directory that contains the files that are available to visitors to a web site, such as pages, images and data. This is the directory that users enter when they first visit your web site, and all URL paths are relative to it. Setting the document root to a non- root directory is necessary to prevent users from being able to access all the files and directories on your web server machine.
Encryption Encryption is the process of transforming information in such a way that it can only be transformed back and read by the intended recipient. Zeus Web Server can be configured to use SSL to encrypt information before sending it to a web browser, which can then decrypt it again. Information is transformed using a pair of keys: a private key and its associ-
ated public key. It is encrypted using one key and decrypted again using the other.
Error page The error page is the page that is displayed when a particular HTTP error occurs. Each type of error has its own HTTP error code and its own error page associated with it.
Fault tolerance Fault tolerance is the ability of a service to continue to respond even when an entity providing that service has failed. For example, a server farm is fault tolerant if it is able to continue processing web requests even when one of its two front-end machines has failed.
Front-end machines
Front-end machines are machines in a server farm that receive requests from users, and pass them on to the back-
end machines. Front-end machines that can determine
which back-end machines are under least load, and pass incoming requests on to them, are load balancer machines. Gateway aliases Gateway aliases enable you to redirect requests for various
parts of your web site, including individual files, entire direc- tories, or all file names that match a certain pattern. The original URL is not changed before it is forwarded to the con- figured web server, and all other data in the HTTP request is preserved and forwarded.
Global htaccess file
The global htaccess file can specify the settings for any file, directory or URL in the Virtual Server’s web site. Its directives are applied to all requests, although they can then be over- ridden by the local htaccess files. It is held outside the docu- ment root. See also htaccess file.
Group A group of Virtual Servers can be thought of as a labelled collection of Virtual Servers. For example, you might create a “FastCGI” group that contains all the Virtual Servers that can run CGI scripts. Groups enable you to identify Virtual Servers with similar configurations quickly, and enable you to edit their configurations together easily. A Virtual Server can be in any number of groups.
Handler A handler specifies which type of third party application has been set up to process particular file types. It passes the specified file requests to the associated application, which processes each and returns the results to the user.
Home directories
Home directories provide a way of relating the system users to their home page directories.
Home page A home page is the page that is displayed when a user accesses a web site without specifying a file name. It can be thought of as being the default page for the web site. See also index file name.
Host Header The Host Header field is used in HTTP/1.1 (and above) to specify the host name and port number (if not using the default port) of the resource being requested. The browser fills the field in from the host name in the original HTTP URL. For example, a request for
http://www.w3.org/pub/WWW/ gives a Host Header of Host: www.w3.org.
Host name The host name for a machine is a unique name that identifies a machine by being associated with a particular IP address using DNS Lookup. It is specified in the form
site.subdomain.domain, and can be thought of as a way of making IP addresses easier for users to recognize and use. Host names enable the IP address associated with a machine to be changed transparently because the DNS record for the machine can simply be updated with the new IP address without affecting the host name. See also alias. htaccess file htaccess files are text files that enable you to specify local configuration rules (directives) that apply to the files in the local directory and its subdirectories. This enables you to localize access rules throughout the document root directory tree, and delegate this control to those who control the local content. See also global htaccess file and local htaccess file. HTTP HTTP (Hypertext Transfer Protocol) is the protocol that web
information. The browser sends requests for information to the web server, and the web server responds with either the requested information or with information indicating why the requested information could not be returned. The cur- rent version of HTTP is HTTP/1.1. See also HTTPS.
HTTP error page See Error page.
HTTPS HTTPS is a secure version of HTTP that uses SSL.
Index file The index file is the file that the browser displays if a users enters a URL that does not include a specific file name. It can be thought of as the default file for a subdirectory. The index file in a web site’s document root is also referred to as the web site’s home page.
Internet The Internet is a network of TCP/IP networks. The Internet provides a number of different services, such as email and the World Wide Web, using a number of different protocols, such as HTTP.
IP address Each computer on the Internet is uniquely identified by an IP address. This is currently a 32-bit number that identifies the network (the network address) and the specific host on that network (the host address), and is usually represented by 4 numbers separated by dots. In practice users rarely use IP addresses directly, but use host names, which are mapped to IP addresses using DNS.
ISP An ISP (Internet Service Provider) is an organization that pro- vides Internet services to its customers such as email, web hosting, Internet connectivity and so on.
Load Balancing Load balancing is the process of distributing requests between the back-end machines in a server farm so that new requests go to the least loaded machines. This means that the back-end machines are used as evenly as possible and can therefore perform most effectively.
Local htaccess file
A local htaccess file can be placed in any directory within the document root. Its settings override the global settings and
any settings in local htaccess files further up the hierarchy. This enables you to configure the behavior of the Virtual Server for segments of the document tree by editing a single file. See also htaccess file.
Log files Log files are text files that record web site activity. You can use them to monitor your web server activity and help diag- nose any problems. For example, you can use the request log file to identify broken URLs or missing files.
Machine name See host name.
MIME types The MIME type is the information returned with each requested file, that the browser uses to determine how to handle and display the file. There are a set of standard MIME types that can be associated with different file extensions. Port number The port number specifies which TCP/IP port the web server is
listening to. It is a 16 bit number that specifies a particular service or application on the machine. Port numbers can be any number between 1 and 65535. Port 80 is the default
HTTP port, and port 443 is the default HTTPS port – that is, it
is the port that is assumed when a user enters a URL using those protocols. If a web server runs on any other port then the port number must be explicitly specified in the URL- for example, http://www.mywebsite.com:8090
Zeus Web Server uses two special ports: the control port and the Admin Server port.
Private key A key that is known only to the key holder, and used either to encrypt information that will be decrypted using the associ- ated public key, or to decrypt information that has been encrypted using the public key. See also Encryption.
Protocol An agreed set of rules used by two entities to communicate with each other.
Public key A key that is publicly known, that is used to encrypt informa- tion so that it can only be decrypted by someone with the associated private key. See also Encryption.
Referrer A referrer is an external web site that links to files on your web site. You can prevent external web sites from linking to specified MIME types.
Request logging Each time a request is made to a Virtual Server, a new entry is made in the Virtual Server’s request log file. The entry can consist of various pieces of information, such as the IP address of the user who made the request, or the name of the URL they requested.
Server farm A server farm is a collection of machines that includes front-
end machines (providing traffic management) and a cluster
of back-end machines (that process the requests). A Zeus server farm also includes an Administration server that man- ages the server farm.
SSL SSL (Secure Sockets Layer) is a commonly used protocol for managing secure communications on the Internet. It uses public key cryptography to provide secure information trans- fer between web servers and browsers. See also Encryption and HTTPS.
Subserver A Subserver is an individual web site with its own host name and document root, that has the same configured function- ality as the Virtual Server that supports it. One Virtual Server can support any number of Subservers, and all of them can be configured and managed just by configuring and manag- ing the Virtual Server.
TCP/IP TCP/IP (TCP over IP) is the networking protocol used by the Internet. The destination machine is usually specified by an
IP address and port number combination.
URL A URL (Universal Resource Locator) identifies the protocol and web site address needed to access a particular resource, in the form method://host_name/filename. For example, http://www.zeus.com/
Virtual Server Virtual Servers enable you to run multiple web sites on one machine, while configuring, managing and running them
independently. A web server must include at least one Virtual Server. There are two types of Virtual Server:
• A hard Virtual Server is a web server that is identified by a particular IP address.
• A soft Virtual Server is a web server that is identified first by the IP address and port combination, and then by a
Host header.
Web browser A web browser is the program that a visitor uses to access the web. It is an HTTP client that requests pages from web servers and displays the response to users.
Web server A web server is the hardware and software that makes pages, image and other documents available on the web. The web server software listens for incoming requests for specified IP addresses and ports on the network, and responds to them. Web servers receive requests for files from web clients (browsers) – specified as URLs- and respond by returning information (usually the file content or the file output). Web servers can range from being able to host simple collections of static pages to being able to support dynamic web sites that provide a robust, reliable, secure e-commerce environ- ment.
Webmaster A webmaster is the person responsible for the content of a particular web site.
Web site address
A web site address is the location information within a URL. It is made up of a domain name and file location, such as www.zeus.com/products/.
Web site alias See Alias. World Wide Web
The World Wide Web is just one part of the Internet. It is the part that uses the HTTP protocol and is made up of the pages, graphics and information that can be accessed from web servers using web browsers.
Index
A
Access logging
see Request logging 43 Accessing
Online documentation 40 Subservers 54
User interface 31
Virtual Server Status page 32 Web sites 41
Activity Monitor 48, 49, 50 Adding
Servers to a cluster see Creating a cluster Admin Server port 31, 55
Administration server component Starting 30
Stopping 30 Adobe Acrobat reader
Configuring 31 Aliases 36 APIs CGI 2 FastCGI 2 ISAPI 2 Java servlets 2 NSAPI 3 PHP 3 ZDAC 3 B Bandwidth throttling 14, 52 Browser Configuring 31 Requirements 24 C Certificate set Generating 52 Certificates
Public certificate requests 16 Signed certificates 15 CGI
Support 2
Cluster traffic analysis page 50 Clusters 11 Creating 55 Load balancing 55 Commands reset_password 59 start-zeus 29 stop-zeus 30 zinstall 25 Committed configuration 40 Committing changes 40 Configuration changes Committing 40
Configuration changes icon 39 Configure icon 39
Configuring Browser 31 Error log file 45 SSL security 51 Contacting support 60 Control port 27, 56 Conventions 5
Creating A cluster 55 Subservers 54 Virtual Servers 34 D Default Logging settings 44 Diagnose icon 39, 41 Disabling Request logging 44 SSL 51
Disk space requirements 23 DNS entries 33
Clusters 55 Subservers 54 Document root names
Subservers 54 Documentation Accessing 40 Domain names Registering 33 Dynamic content 8 E Email address
Webmaster of web site 37 Enabling SSL security 51 Encryption keys 15 Error logging 17, 45 Configuring 45 File location 45 Error logging levels
FATAL 17 INFO 17 SERIOUS 17 WARN 17 F FastCGI Support 2 FATAL error logs 17
Files
Global error log file 45 Request logging 44 FrontPage Support 3 G Generating Certificate set 52 Private keys 15 Self-signed certificates 15 H
Hard Virtual Servers 10 Help
see Online documentation Host Headers 10
https 52 I Icons
Configuration changes icon 39 Configure icon 39
Diagnose icon 39, 41