Using policy routing to redirect traffic
The-Art of caching system traffic without needing user / visitor aspect setting.
What is transparent caching?
Transparently proxying / caching network traffic without requiring user configuration or information. A method to simplify caching for that end user Forces all customers to use the cache.
Why use transparent caching? ď Ź
ď Ź
Ease of use. No setup needed by the consumer. Capturing all customers. No users may avoid the cache.
What is involved?
TCP level routing Reverse NAT or related technology to hijack port 80 traffic. A proxy with some knowledge of transparent proxy server A cache
Tools available
TCP stage Routing
Policy routing / path maps
TCP / layer 4 switches
with or without NAT
Cisco WCCP
Host level NAT
Linux firewall signal
FreeBSD firewall signal
IP-Filter
Using policy routing to redirect traffic ď Ź
A standard router configured to route TCP port 80 to the cache server of cheap proxy. Internet
User 1 User 2 User 3 User ..
Policy routing (cont.)
Gains Can usually be deployed without extra equipment
Disadvantages
Only fixed routing
No fault tolerance. Port 80 traffic disrupted if cache machine fails. More CPU load on the router
Running the cache on a router ď Ź
Small network / firewall. Host used as router with anonymous proxy. Router / Cache Server
Internet
User 1 User 2 User 3 User ..
Caching router / firewall
Gains Can usually be deployed without extra equipment
Disadvantages
Only fixed routing
No fault tolerance. Port 80 traffic disrupted if cache machine fails. More CPU load on the router
Cisco Web Cache Control Protocol (WCCP)
Robotic setup. Private Proxy servers announce their presence to the hub.
Load balancing
Fault recovery
Industrial Licensing needed. Not currently an option at no cost software.
TCP switch benefits
May bypass the cache if it malfunctions
Excellent stability
May distribute the strain on multiple cache servers Can do the mandatory NAT, permitting the use of any OS to the cache server. Some do HTTP proxy translation, enabling the usage of any proxy software.
TCP switch drawbacks ď Ź ď Ź
An additional expensive pack to buy proxy Utilizing NAT demands transition dealer support in the application to support old browsers.
Problems related to request formats
A transparent proxy must restore the Website of the request. Host: headers not necessarily accessible. HTTP/1.1 feature or 1.0 add on. INTERNET protocol address from NAT translation.
What happens at the TCP level?
Normal communication / Private proxy servers
IP-BASED routing
TCP is end-to-end
One IP address, one Host
Transparent proxying
TCP based routing
TCP isn't any longer end-to-end
One INTERNET protocol address, “multiple hosts”
Problems at the TCP level
TCP usually relies on two IP practices. TCP and ICMP. Of the just TCP can be easily redirected. ICMP is required for Path MTU discovery. TCP resets if your single package moves another course bypassing the redirection.
Things to consider when configuring OS level NAT
Try not to affect traffic to/from the cache server-host. Make sure that the traffic is not redirected back once again to the SSL private proxy. Anticipate to do packet level traces, ideally from the separate container.
Recommended steps when building a transparent proxy
Think it over. Could it be really necessary?
Assemble and test the proxy-server
Change NAT on the proxy-server
Test it employing a local LAN buyer
Create TCP level routing.
Common problems
Interaction hangs for many consumers
Probably caused by MTU related issues.
Connection reset problems
Terrible performance
Maybe CPU bottleneck in the modem with best private proxy.
Summary
Clear caching is an excellent software generally in most configurations to help ease user side setup. For the same goals are achieved by many automatic instructions on how to configure proxy settings. It's some important restrictions. Not really a full replacement for standard proxying.
Thanking you... For more info log on too... http://proxiesforent.com