About Internet Connectivity

The HTTP service provides functionality for deploying web applications and for making deployed web applications accessible by Internet clients. HTTP services are provided by two kinds of related objects: listeners and virtual servers.

The following topics are addressed here:

• About HTTP Network Listeners

• About Virtual Servers

About HTTP Network Listeners

An HTTP listener, also known as a network listener, is a listen socket that has an Internet Protocol (IP) address, a port number, a server name, and a default virtual server. Each virtual server provides connections between the server and clients through one or more listeners. Each listener must have a unique combination of port number and IP address. For example, an HTTP listener can listen for a host on all configured IP addresses on a given port by specifying the IP address 0.0.0.0. Alternatively, the listener can specify a unique IP address for each listener while using the same port.

Because an HTTP listener is a combination of IP address and port number, you can have multiple HTTP listeners with the same IP address and different port numbers, or with different IP addresses and the same port number (if your host was configured to respond to these addresses). However, if an HTTP listener uses the 0.0.0.0 IP address, which listens on all IP addresses on a port, you cannot create HTTP listeners for additional IP addresses that listen on the same port for a specific IP address. For example, if an HTTP listener uses 0.0.0.0:8080 (all IP addresses on port 8080), another HTTP listener cannot use 1.2.3.4:8080. The host running the Enterprise Server typically has access to only one IP address. HTTP listeners typically use the 0.0.0.0 IP address and different port numbers, with each port number serving a different purpose. However, if the host does have access to more than one IP address, each address can serve a different purpose.

To access a web application deployed on Enterprise Server, use the URL http://localhost:8080/ (or https://localhost:8081/ for a secure application), along with the context root specified for the web application.

To access the Administration Console, use the URL https://localhost:4848/ or http://localhost:4848/asadmin/ (console default context root).

About Virtual Servers

A virtual server, sometimes called a virtual host, is an object that allows the same physical server to host multiple Internet domain names. All virtual servers hosted on the same physical server share the IP address of that physical server. A virtual server associates a domain name for a server (such as www.aaa.com) with the particular server on which Enterprise Server is running. Each virtual server must be registered with the DNS server for your network.

Do not confuse an Internet domain with the administrative domain of Enterprise Server.

For example, assume that you want to host the following domains on your physical server: www.aaa.com, www.bbb.com, and www.ccc.com. Assume that these domains are respectively associated with web modules web1, web2, and web3. This means that the following URLs are handled by your physical server:

http://www.aaa.com:8080/web1
http://www.bbb.com:8080/web2
http://www.ccc.com:8080/web3

The first URL is mapped to virtual server www.aaa.com, the second URL is mapped to virtual server www.bbb.com, and the third is mapped to virtual server www.ccc.com. For this mapping to work, www.aaa.com, www.bbb.com, and www.ccc.com must all resolve to your physical server’s IP address and each virtual server must be registered with the DNS server for your network. In addition, on a UNIX system, add these domains to your /etc/hosts file (if the setting for hosts in your /etc/nsswitch.conf file includes files).