Technical data

52 ServerIron ADX Advanced Server Load Balancing Guide

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Other transparent cache switching options

Configuring destination NAT

Destination NAT can be configured either under a cache server or a cache group as shown in the

following commands:

For a cache server

ServerIronADX(config)# server cache-name server1 207.95.5.11

ServerIronADX(config-rs-server1)# dest-nat

ServerIronADX(config-rs-server2)#

For a cache group

ServerIronADX(config)# server cache-group 1

ServerIronADX(config-tc-1)# dest-nat

Syntax: [no] dest-nat

Source MAC address tracking for TCS

If content is not found locally, some cache servers will initiate a connection to the Internet using the

same TCP parameters as the incoming client connection (source IP:source port destination

IP:destination port), which can cause a conflict with the original client connection.

For such situations, Brocade enables you to track the source MAC address of the incoming packet.

If the source MAC address is that of the cache server, ServerIron ADX TCS will consider this

connection as separate from the conflicting client connection.

To configure source MAC address tracking, enter the server cache track-src-mac command such as

in the following example:

ServerIronADX(config)# server cache track-src-mac

Syntax: [no] server cache track-src-mac

If a cache server has two interfaces connected to a ServerIron ADX including one for Internet

traffic, the “alias-name” must be configured as shown in the following:

ServerIronADX(config)# server cache-name cs1-dummy 1.1.1.2

ServerIronADX(config-rs-cs1-dummy)# exit

ServerIronADX(config)# server cache-name cs1 1.1.1.1

ServerIronADX(config-rs-cs1)# alias-cache cs1-dummy

ServerIronADX(config-rs-cs1)#

Configuring source NAT

Normally, when the ServerIron ADX redirects a client’s web request to a cache server, the

ServerIron ADX translates the destination MAC address of a client request into the MAC address of

the cache server. However, the ServerIron ADX does not translate the source or destination IP

addresses in the client’s request.

Generally, in network topologies where the ServerIron ADX and cache server are directly connected

or connected through a Layer 2 switch or bridge, the cache’s response to a client query always

passes back through the ServerIron ADX. The ServerIron ADX uses the cache response to assess

the health of the cache server. When the ServerIron ADX passes a cache response to the client, the

ServerIron ADX assumes the cache server is healthy.