Proxying with/without listen in server block

[tcbarrett]

Am I missing this:

"If a server is the only server for a listen port, then nginx will not test
server names at all (and will not build the hash tables for the listen
port). However, there is one exception. If a server name is a regular
expression with captures, then nginx has to execute the expression to get
the captures."

http://nginx.org/en/docs/http/server_names.html

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,241824,241826#msg-241826