F5 BIG-IP LTM Specialist: Maintain and Troubleshoot — Question 195

An LTM Specialist has configured a virtual server for www.example.com, load balancing connections to a pool of application servers that provide a shopping cart application. Cookie persistence is enabled on the virtual server. Users are able to connect to the application, but the user's shopping cart fails to update. A traffic capture shows the following:
Request:
GET /cart/updatecart.php HTTP/1.1

Host: www.example.com -

Connection: keep-alive -

Cache-Control: max-age=0 -
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.4 (KHTML, like Gecko) Chrome/22.0.1229.94 Safari/537.4
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-EncodinG. gzip,deflate,sdch

Accept-LanguagE. en-US,en;q=0.8 -
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
CookiE. BIGipServerwebstore_pool=353636524.20480.0000
Response:

HTTP/1.1 200 OK -
DatE. Wed, 24 Oct 2012 18:00:13 GMT
Server: Apache/2.2.22 (Ubuntu)
X-Powered-By: PHP/5.3.10-1ubuntu3.1
Set-CookiE. cartID=647A5EA6657828C69DB8188981CB5; path=/; domain=wb01.example.com

Keep-AlivE. timeout=5, max=100 -

Connection: Keep-Alive -

Content-TypE. text/html -
No changes can be made to the application.
What should the LTM Specialist do to resolve the problem?

Answer options

• A. Use an iRule to rewrite the cartID cookie domain.
• B. Create a universal persistence profile on the cartID cookie.
• C. Enable source address persistence as a fallback persistence method.
• D. Create a cookie persistence profile with "match across services" enabled.

Correct answer: A

Explanation

The correct answer is A because the cartID cookie is being set with a different domain (wb01.example.com) than the virtual server (www.example.com), which prevents it from being sent back to the server on subsequent requests. The other options do not address the domain mismatch issue that is causing the shopping cart to fail to update.