Netra Proxy Cache Array Configuration Guide

Chapter 1 Preparing for Installation and Configuration

Why You Should Read This Chapter

You will spend less time in bringing the Netra Proxy Cache Array online if you read this chapter and then perform the configuration tasks than if you dive directly into the configuration tasks.

Configuration of a Netra Proxy Cache Array involves concepts and terminology that might not be familiar to you. Also, most of the work in configuring an array is in the preparation--for example, obtaining IP addresses and assigning a Domain Name Service (DNS) subdomain to the array--rather than in the interaction with the administrative web pages.

Configuration Overview

The following figures illustrate the installation and configuration tasks involved with bringing up a Netra Proxy Cache Array.

Figure 1-1 illustrates hardware-related installation tasks. Instructions for these tasks are presented in the hardware documentation that accompanies the Netra Proxy Cache product.

Figure 1-1 Hardware Installation

The service network is the LAN over which your array hosts interact with clients. The control network is a private network used by the array software. These terms are described in detail in "Key Concepts".

Figure 1-2 gives a high-level view of the tasks required to configure the software for a Netra Proxy Cache Array.

Figure 1-2 Software Configuration Sequence

The tasks in the boxes in Figure 1-2 are described in detail in Chapter 2, Initial Host Configuration" and Chapter 3, Proxy Cache Array Configuration."

Key Concepts

Understanding of the concepts listed below is required to configure a Netra Proxy Cache Array. Please refer to Figure 1-3 as you read the following definitions.

name of the Netra Proxy Cache Array

The set of hosts that form a Netra Proxy Cache Array are known to clients by a single name--the name of the DNS subdomain formed by the array--and, in fact, the array appears as a single proxy cache service to clients.

role of DNS

Each Netra Proxy Cache Array has one host that acts as the authoritative server for zone formed by the array. The remaining array hosts act as hot spares for the DNS server. Array software modifies the DNS round robin to provide load-balancing. An existing DNS server must delegate the subdomain formed by the Netra Proxy Cache Array. Chapter 2, Initial Host Configuration" provides an example of how to do this.

Netra Proxy Cache Array software

Consists of a daemon and software objects that run on each of the machines in a Netra Proxy Cache Array. The array software is what enables multiple servers to provide a single, reliable proxy cache service. On a periodic basis, the array software monitors the health (reachability, load, presence of server processes) of the hardware resources and proxy cache service on each machine. It also monitors the instance of the DNS running on one of the hosts in the array.

control network

An isolated (private) subnet over which the array software sends snapshots of the health of each machine in the array. Netra Proxy Cache Servers are equipped with a second network interface (hme1) to enable connection to a control network. This second interface is referred to as the control interface.

service address

The resource managed by the array software. This is a logical IP address that is associated with the proxy cache service on each host in the array. (There is also a service address associated with the DNS on one machine.) If a machine fails or becomes overloaded, array software can remove the availability of the service address or move the address to a different machine in the array. A critical distinction between a service address and the host IP address is that the service address can move to a different host in the array, while the host address remains fixed.

service network

The network over which server-client interactions occur. The service network is, most often, the local area network (LAN) over which clients access a variety of network services. A Netra Proxy Cache Server connects to the service network through the service interface, which is the interface (hme0) associated with the server's host name. There is no exchange of packets between the service and control networks.

Table 1-1 Interfaces and Required Addresses


Interface Name	Use	Addresses Associated with	Subnet Number
`hme0`	service interface, used to connect to service network	host IP address service address for proxy cache service service address for DNS (on one host in array)	Same subnet number used for host IP address and service address(es)
`hme1`	control interface, used to connect to control network	control address	Different subnet number from that used for host name and service address(es)

Figure 1-3 illustrates the concepts described above.

Figure 1-3 Example Netra Proxy Cache Array

The addresses shown in Figure 1-3 are used as examples in the configuration tables that follow. It is important to note relationship among addresses:

The host, proxy cache service, and DNS service addresses all use the same subnet number

The control addresses use a different subnet number from that used for the addresses mentioned in the previous bullet

Hardware Required

For the control network, you need an Ethernet hub and an RJ-45 cable for each machine, to connect the hme1 interface on each host in the array to the hub. It is not critical for the operation of the control network that your hub support 100 Mbs. The hme1 interface supports either 10 or 100 Mbs.

If you have a two-host array and do not have a hub, you need a back-to-back RJ-45 cable.

If you plan to establish a TTY connection to your Netra Proxy Cache Server, you need a serial cable. See Appendix A, Establishing a tip Connection," for requirements.

Configuration Tables

This section contains tables that you can use when performing the tasks described in Chapter 2, Initial Host Configuration." It is recommended that you make a copy of these pages and fill out the tables before starting the procedures in Chapter 2, Initial Host Configuration."

Initial Host Configuration

Initial host configuration divides into the following sequence:

Network interface configuration
Completing initial host configuration (time zone, root password, and so on)

You can perform network interface configuration by either of two ways, the TTY method or the diskette method. These methods, as well as the entire initial host configuration process, are illustrated in Figure 1-4.

Figure 1-4 Initial Host Configuration

In terms of what you need to know, there is no difference between the TTY and diskette methods. In the diskette method, you enter the Netra Proxy Cache Server's host name during network interface configuration. In the TTY method, you specify a host name following network interface configuration.

Table 1-2 lists the data required for network interface configuration. You perform this configuration on each host in a Netra Proxy Cache Array. Among the data in the table, only the host name and IP address are unique to a single host. The remaining items apply to all hosts in the array.

Table 1-2 Data Required for Network Interface Configuration


Parameter Name	Description	Enter Value Here:
network interface (TTY method only)	This is the network interface (`hme0`) with which your host name is associated. Your server's other interface (`hme1`) is used for the control network. Example: `hme0`	`hme0`
host name of Netra Proxy Cache Server (diskette method only)	For convenience, this should be registered in your NIS and/or DNS maps. Example: `host1`
host IP address of Netra Proxy Cache Server	Use dotted decimal notation. Make a note of this address. You will use it when configuring the Netra Proxy Cache software. Example: 129.144.118.2
netmask	Netmask used in service network, in dotted decimal notation. Example: 255.255.255.0

After you perform network interface configuration, you point a browser at your Netra Proxy Cache Server and complete initial host configuration using the product's administration web pages. Table 1-3 lists the data required to complete initial host configuration.

Table 1-3 Data Required to Complete Initial Host Configuration


Parameter Name	Description	Enter Value Here:
time zone	Time zone in which host resides. Example: US/Pacific
locale	Locale in which host resides. Example: English (Only choice in the current release)
host name of Netra Proxy Cache Server (only if you performed TTY method for network interface configuration)	For convenience, this should be registered in your NIS and/or DNS maps. Example: `host1`
System administrator alias	Email addresses that will receive mail addressed to `root@<netra host name> or` `Postmaster@<netra host name>`.
root password	There is no default. That is, you start with no root password.
administration account name	The administration account name is `setup`.
administration password	The default password is `setup`. You need this password to access the Netra Proxy Cache administration web pages and the `setup` system account.
DNS domain name (if DNS is used)	Domain in which your Netra Proxy Cache host resides. Examples: `acme.com` or `sales.acme.com`
IP address of DNS server (if DNS is used)	Use dotted decimal notation. This is the DNS server outside of the Netra Proxy Cache Array that will resolve the name of the subdomain formed by the array. Example: 129.144.91.24
NIS domain name (if NIS is used)	NIS domain in which your Netra Proxy Cache host resides. Examples: `acme.com` or `eng.acme.com`

Choosing an Administrative Host

Following initial configuration on each host in the Netra Proxy Cache Array, you configure the Netra Proxy Cache software. You perform this configuration on one host in the array. The choice of which machine is arbitrary. We refer to the machine on which you perform configuration as the administrative host.

My administrative host is: ______________________________________ .

Proxy Cache Service Configuration

Use your entries in the following tables to respond to prompts in the administrative web pages. In these pages, configuration is broken down as follows:

Proxy cache configuration

Array configuration

Array member configuration

The tables correspond to pages you find in the administrative web pages.

Use the values you enter in Table 1-4 and Table 1-5 to configure the proxy cache service.

Table 1-4 Data for Basic Proxy Cache Configuration


Parameter Name	Description	Enter Value Here:
HTTP port	Port number used by the Netra Proxy Cache Server for receiving web requests. Most users can accept the default of 8080. Example: 8080
Inside firewall?	In a corporate setting, most proxy cache servers are inside a firewall.
Domains inside firewall	For domains not on this list, if the server cannot find a requested object in its local cache, it always tries to fetch the URL from a parent or sibling.



Parent proxies	If you are inside a firewall, you probably have a parent proxy. You can have multiple parents. See following table.

The Netra Proxy Cache Server supports multiple parent and sibling proxies. For each parent of your server, find out the following information:

The port it uses for HTTP

The port it uses for the Inter Cache Protocol (ICP)

Whether it supports tunneling of the Secure Sockets Layer (SSL) protocol
Whether it supports persistent connections (as supported by popular browsers such as Netscape Navigator and Internet Explorer)

(Netscape and Netscape Navigator are trademarks of Netscape Communications Corporation. Microsoft and Internet Explorer are trademarks of Microsoft Corporation.)

If your parent is a Netra Proxy Cache Server, keep in mind that the server uses default port numbers of 8080 and 3130, for HTTP and ICP, respectively. Also the Netra Proxy Cache Server supports SSL tunneling and persistent connections.

If your Netra Proxy Cache Server is part of an array, sibling configuration is automatic: there is no need to specify other machines in the array as your siblings. You can specify machines not in the array as siblings.

If your parent is not a Netra Proxy Cache Server, consult the documentation for that server to determine whether it supports ICP, SSL tunneling, and persistent connections.

Table 1-5 Parent Proxies (Enter Names and Values)


Parent Name	HTTP Port	ICP Port (Enter 0 if ICP not supported)	Support SSL tunneling? (y/n)	Support persistent connections (y/n)

Use the values in Table 1-6 to complete basic array configuration.

Table 1-6 Data for Basic Array Configuration


Parameter Name	Description	Enter Value Here:
control network	Subnet number of the control network, expressed as, for example, `x.x.x.`0 for a Class C netmask. It is recommended that you use 10.0.0.0 or 192.168.0.0. Example: 192.168.89.0
control network netmask	You can probably accept the default of 255.255.255.0. Example: 255.255.255.0
service network	Subnet number of the service network, expressed as, for example, `x.x.x.`0 for a Class C netmask. This value must be different from the subnet number used for the control network. Example: 129.144.118.0 (Note that this is the subnet portion of the host IP address and of the proxy cache and DNS service addresses)
service network netmask	The default is 255.255.255.0. Example: 255.255.255.0
Proxy cache domain name	Name of the DNS domain formed by the hosts in the array. Example: `cache.acme.com`
Array DNS service address	An IP address associated with the DNS on the array DNS server. As a service address, this address is subject to moving to a different host upon host failure. Example: 129.144.118.200
Array DNS host name	Host name of the host within the array that will act as the DNS server for the domain formed by the array. You can choose any machine in the array. It is strongly recommended that you use your administrative host. Example: `host1`

Use the data in Table 1-7 to complete basic array member configuration.

Table 1-7 Data for Basic Array Member Configuration


Parameter Name	Description	Enter Value Here:
For each host in the array:
host name	Just as you entered it during initial configuration. See Table 1-1. Example: `host1`
host address	IP address associated with `hme0` interface. This is the address you specified as the IP address of the Netra Proxy Cache Server during initial configuration. See Table 1-1. Unlike a service address, this address is not subject to moving to a different host. This address must have the same subnet number that you specified for the service network. Example: 129.144.118.2
control address	IP address associated with the `hme1` interface, used to connect to the control network. This address must have the same subnet number that you specified for control network. See Table 1-5. Example: 192.168.89.1
service address	An IP address associated with the proxy cache service on a host. As a service address, this address is subject to moving to a different host upon host failure. This address must have the same subnet number as the host address, above. This is also the same subnet number you specified for the service network. See Table 1-5. Example: 129.144.118.100

Netra Administration GUI Icons

You perform a portion of the software configuration of a Netra Proxy Cache Array or Server through a set of administration web pages. Table 1-7 displays the icons used to navigate through and display the status of the Netra Proxy Cache administration pages.

Table 1-8 Netra GUI Icons


Icon	Description
	Home icon. This navigation icon returns to the Netra Main Administration page.
	Help icon. This icon will open the help window, where the help pages are displayed. The help window can be moved, iconified or dismissed independent of the main browser window. The help window will update the help pages as requested.
	Back Arrow icon. This navigation icon goes back one page.
	Top-of-Module icon. This navigation icon goes to the first administration page of a particular module.
	Forward Arrow icon. This navigation icon moves forward to the next initial configuration module.
	Reminder icon. This icon calls attention to important messages in response to successfully configuring a module.
	Error icon. This icon indicates errors in configuring a module.
	Success icon. This icon shows that a module has been configured successfully.

Summary

To summarize the data you need:

For each host in Netra Proxy Cache Array, you need three IP addresses, the address associated with the host name (which remains fixed to a host), a service address associated with the proxy cache service (which is subject to moving to a different host in the array), and a control address.

For one host in the array, you need an IP address in addition to those mentioned above: a service address for the DNS that runs on that host.

You need a DNS domain name for the subdomain (zone) formed by the array. For example, if your domain name is acme.com, you might choose cache.acme.com.

You need a few items in addition to these. However, with this minimal set you can configure the array and later make changes to the configuration to suit your needs.