id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
906	Header duplicated in case of NGINX and NodeJS	cecile.saintmartin@…		"We're using NGINX on 2 servers :
First one (Front server): NGINX + NodeJS
Second one (Backend server) : NGINX + other application

The request goes through the first server to the backend server, this part is Ok.
When the backend returned the reponse, NGINX add a ""Vary"" header.
Then the response goes back through NodeJS on the Front server. NodeJs lower case all headers (native behaviour) => the header ""Vary"" is transformed into ""vary"" (header name).
Then the response goes back on NGINX on the front server and NGINX add a second header ""Vary"".
So finally we have to headers : one ""Vary"" and one ""vary"". 
This behaviour has been observed with other header : X-ForwardedFor for example.
So it seems that NGINX doesn't detect the existing header ""vary"" and add a new one.
We consider it as a bug because according to RFC, header names are case INSENSITIVE."	defect	closed	major		nginx-core	1.8.x	duplicate	header duplication			nginx/1.8.0