KEMP Technologies LoadMaster 1500 Installation And Configuration Manual Download

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3. URL Host Based Persistency

This unique feature of the LoadMaster allows a single balanced site to support multiple addresses. Each

address with the same host will then be routed to the same real server as long as the persistency duration is

valid. This is useful when a single site is addressed by different URLs (i.e. mysite.org and mysite.foryou.edu

could both go to the same virtual address but they could be handled by different real servers).

4. Cookie Based Persistency

In this mode, the real servers supply a server specific cookie, which the LoadMaster uses to determine to

which real server the next request with the same cookie should be sent.

When using passive cookie handling, each real server must be modified to send a “Set-Cookie” record on each
request (which does not already have a cookie value set).

(For an example refer to Section O.2)

5. Cookie/Source (Cookie or IP source) Based Persistency

This method functions exactly like “cookie based persistency” when the client browser returns a cookie. If

however the client does not return a cookie, either because the user has disabled them or has ignored the
cookie, then the clients IP address will be used as the persistency key.

6. Active Cookie Based Persistency

In this mode, the LoadMaster inserts a cookie into the data stream returned to the client when a request is

made. This cookie is used to identify which real server handled the request. When the client again makes a

request, the cookie will be sent back to the LoadMaster, which will then use the value of the cookie to direct
the request to the same real server as before. When using active mode, no modifications must be done to the

real servers. The Balancer administers all cookies for the servers.

7. Active Cookie/Source (Active Cookie or IP source) Based Persistency

This method functions exactly like “active cookie based persistency” when the client browser returns a cookie.
If however the client does not return a cookie, either because the user has disabled them or has ignored the

cookie, then the clients IP address will be used as the persistency key.

8. Cookie hash Persistency

This method “hashes” the value of all cookies sent by the client to determine which real server to direct the

request to. All requests that have the same set of cookies will be sent to the same real server.

9. Port Following

When using “shopping cart” like services where a user selects items and adds them to a list, any of the

previous types of persistency can be used. When the user then decides to pay for the items, this is normally

performed using a secure SSL (https) service. When port following is turned on, the real server where the

“shopping cart” connection is active will be selected for the SSL session. This selection will only occur when a
connection is still open from the same client (as determined by the source IP address), and if the SSL service

has the same IP address as the “shopping cart” service.

I.e. if a connection is made to the HTTP service of www.somewebsite.com, and then a new SSL connection is

made to the same address, then the SSL session will be directed to the same real server as the original HTTP

service.

Note: This only works correctly if both services have the same set of real servers.