Brocade Communications Systems ServerIron ADX 12.4.00 Service Manual download pdf (Page 70)

58 ServerIron ADX Advanced Server Load Balancing Guide

53-1002435-01

Other TCS options

NOTE

You cannot use the cache server spoofing feature with the Reverse Proxy SLB feature on the same

ServerIron ADX.

When a cache server makes a request for content from the origin server, it can do one of the

following:

• The cache server replaces the requesting client's IP address with its own before sending the

request to the Internet. The origin server then sends the content to the cache server. The

cache server stores the content and sends it to the requesting client, changing the source IP

address from its own to the origin server's IP address.

• The cache server does not replace the requesting client's IP address with its own. Instead, the

cache server sends the request to the Internet using the requesting client's IP address as the

source. This allows the origin server to perform authentication and accounting based on the

client’s IP address, rather than the cache server’s IP address. This functionality is known as

cache server spoofing.

When cache server spoofing support is enabled, the ServerIron ADX does the following with

requests sent from a cache server to the Internet.

1. The ServerIron ADX looks at the MAC address to see if the packet is from a cache server. Note

that the ServerIron ADX and the cache server cannot be separated by any router hops; they

must be on the same physical segment. The ServerIron ADX uses an ARP request to get the

MAC address of each configured cache server.

2. If the MAC address indicates that the packet is from a cache server, the ServerIron ADX checks

the source IP address. If the source IP address does not match the cache server's IP address,

the ServerIron ADX concludes that this is a spoofed packet.

3. The ServerIron ADX creates a session entry for the source and destination (IP address, port)

combination, and then sends the request to the Internet.

When the origin server sends the content back, the ServerIron ADX looks for a session entry that

matches the packet. If the session entry is found, the ServerIron ADX sends the packet to the

appropriate cache server.

To enable cache server spoofing support, enter commands such as the following.

ServerIronADX(config)# server cache-group 1

ServerIronADX(config-tc-1)# spoof-support

Syntax: [no] spoof-support

The no form of the command disables cache server spoofing support. Cache server spoofing

support is disabled by default.

To display the number of spoofed packets encountered by the ServerIron ADX, enter the following

command.

1 2 ... 65 66 67 68 69 70 71 72 73 74 75 ... 135 136

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Brocade Communications Systems ServerIron ADX 12.4.00 Service Manual Page 70