ACE for transparent proxying and load balancing

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Sep 9th, 2008
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We are intending to use and ACE appliance to re-direct web traffic to a set of proxy servers. The proxy mechanism is transparent proxy, and there for the clients IP address are not VIPs but real IPs on the internet. I'm unclear on how to set this up. Especially, how to do transparent redirection of traffic on the ACE(and whether that is possible for that matter)

Can some one pls help.

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Overall Rating: 5 (2 ratings)
Gilles Dufour Tue, 09/09/2008 - 01:42
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you need to setup a serverfarm that has your proxy defined as real server.

Then use the keyword 'transparent' inside the serverfarm to make it transparent.

Create a class-map to catch the traffic you need.


class-map Http-Proxy

match port tcp eq 80

Then associate the class-map and serverfarm in a policy


policy-map type loadbalance first MyProxy

class class-default

serverfarm ....

policy-map multimatch VlanX

class Http-proxy

loadbalance policy MyProxy

loadbalnce vip inservice



thedinuka Tue, 09/09/2008 - 02:07
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Thanks. I understand the configs on classmap and policy map. But whats the requirement to define the server farm as transparent?

also can you point out how to set that up

thanks again

Gilles Dufour Tue, 09/09/2008 - 03:15
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By setting the serverfarm in transparent mode you instruct ACE not to nat the destination address when forwarding to the proxy.

The default mode is to nat the destination with the real server ip address.

The serverfarm config would look like this :

serverfarm MyProxy


rserver Proxy 1




thedinuka Tue, 09/09/2008 - 03:29
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great, that was really helpful, But for this to happen is there a specific constraint on the operating mode (routed or bridged?)

also, is there a specific doc on which i can find this info(like the transparent command on the server farm config?)

you are being very helpful and I really appreciate that


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