cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
Chitra.Lal
AppDynamics Team

Problem:

Users with a mobile app monitoring applications behind an NGINX server will experience missing server-side correlation. This is due to a security standard used by NGINX that acts on underscores in headers such as the metadata passed by the App agent. 

 

Example:

["Accept: application/json" --header "ADRUM: isAjax:true" --header "ADRUM_1: isMobile:true"]

 

According to NGINX documentation, this is done in order to prevent ambiguities when mapping headers to CGI variables, as both dashes and underscores are mapped to underscores during that process.

 

Diagnosis: 

Get the response header from the client side of the network with the following command:

curl -v --header "ADRUM: isAjax:true" --header "ADRUM_1: isMobile:true" <http[s]://<endpoint>>
 
Expected: abbreviated response headers, like the following.
< ADRUM_0: g:a3e4e4a4-0406-4fc2-819e-ea6521359a3c84480 
< ADRUM_1: i:563
< ADRUM_2: n:customer1_cef43e07-de57-4fce-939a-54a6c5dcdf56
 
Instead, Mobile Agent results:
< ADRUM_0: clientRequestGUID:3de4f995-e0ba-4d59-971f-d653e1ea44cf
< ADRUM_1: globalAccountName:customer1_7cc5e33b-579e-4e57-b302-b1eb63b30a0c
 

Solution:

The user must explicitly set underscores_in_headers on;, to prevent NGINX from silently dropping HTTP headers that contain underscores.

 
Version history
Last update:
‎10-12-2018 02:09 PM
Updated by:
June 26 Webinar
Discover new Splunk integrations and AI innovations for Cisco AppDynamics.


Register Now!

Observe and Explore
Dive into our Community Blog for the Latest Insights and Updates!


Read the blog here