NGINX SSL Reverse Proxy Cache Caching Content only for individual clients

We are having some trouble setting up NGINX as a reverse SSL proxy cache.

We have successfully got everything working except the content caching feature.

The caching feature works, and displays a "X-Cache: HIT" header for the second request for a single client - but if a different client tries to access the same resource, they get a "X-Cache: MISS" on their first request.

How can we enable caching globally and not just on a per client basis?

Thank you for your help in advance.

Code on NGINX Proxy:

http {
server_tokens off;
include mime.types;
default_type application/octet-stream;

#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';

#access_log logs/access.log main;

sendfile on;
#tcp_nopush on;

#keepalive_timeout 0;
keepalive_timeout 65;

#gzip on;
proxy_cache_path /cache keys_zone=one:10m
loader_threshold=300 loader_files=200
max_size=200m;
server {

proxy_cache one;

listen 195.224.144.000:443 ssl spdy;
server_name www.mydomain.net;

ssl_certificate /certificates/mydomain.cer;
ssl_certificate_key /certificates/mydomain.key;

ssl on;
ssl_session_cache builtin:1000 shared:SSL:10m;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA';
ssl_prefer_server_ciphers on;


location / {
ModSecurityEnabled on;
ModSecurityConfig modsecurity.conf;
add_header X-Cache $upstream_cache_status;
proxy_set_header Host $host;
proxy_force_ranges on;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_pass https://195.224.144.000;
proxy_read_timeout 180s;

}
}