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Rewrite Cookie Mode
In rewrite cookie mode, the Web switch generates the cookie value on behalf of the server,
eliminating the need for the server to generate cookies for each client.
Instead, the server is configured to return a special persistence cookie which the switch is con-
figured to recognize. The switch then intercepts this persistence cookie and rewrites the value
to include server-specific information before sending it on to the client. Subsequent requests
from the same client with the same cookie value are sent to the same real server.
Rewrite cookie mode requires at least eight bytes in the cookie header. An additional eight
bytes must be reserved if you are using cookie-based persistence with Global Server Load Bal-
ancing (GSLB).
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defined in the URL.
Example:
Client
Figure 16-4 Rewrite Cookie Mode
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the responding server; that is, the value can be used for hashing into a real server ID or it can
be the real server IP address. The rewritten cookie value is encoded.
212777-A, February 2002
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Rewrite cookie mode only works for cookies defined in the HTTP header, not cookies
The following figure shows rewrite cookie mode operation:
2. Client visits the Web site via HTTP request
Proxy Firewall
5. Web switch rewrites the cookie to contain a
server ID for hashing on subsequent requests
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When the Web switch rewrites the value of the cookie, the rewritten value represents
1. Configure switch to rewrite cookie values
3. Switch selects
Internet
Web Switch
Web OS 10.0 Application Guide
server via SLB
Web Server
4. Server HTTP response
includes empty cookie
Chapter 16: Persistence
Farm
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