redmine installation not working through nginx and thin - nginx

Question

I've installed Redmine on an Ubuntu 13.04 server.
This installation worked fine and I confirmed Redmine was working through the WEBrick server (as per redmine documentation).
To make things more stable I want to run Redmine behind Nginx & Thin.
With this part I run into problems as Nginx reports getting timeouts:
2013/07/19 07:47:32 [error] 1051#0: *10 upstream timed out (110: Connection timed out) while connecting to upstream, .......
Thin Configuration:
---
chdir: /home/redmine/app/redmine
environment: production
address: 127.0.0.1
port: 3000
timeout: 5
log: log/thin.log
pid: tmp/pids/thin.pid
max_conns: 128
max_persistent_conns: 64
require: []
wait: 10
servers: 1
daemonize: true
I can see Thin is running, the pid file is created and a logfile is started.
I see no further additions to the logfile when doing requests.
Nginx configuration:
upstream redmine {
server 127.0.0.1:3000;
}
server {
server_name redmine.my.domain;
listen 443;
ssl on;
ssl_certificate /home/redmine/sites/redmine/certificates/server.crt;
ssl_certificate_key /home/redmine/sites/redmine/certificates/server.key;
access_log /home/redmine/sites/redmine/logs/server.access.nginx.log;
error_log /home/redmine/sites/redmine/logs/server.error.nginx.log;
root /home/redmine/app/redmine;
location / {
try_files $uri #ruby;
}
location #ruby {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_read_timeout 5;
proxy_pass http://redmine;
}
}
I can see additions to the Nginx log.
Can anyone give me a hint on where to find the problem in this?
Current result of iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT tcp -- anywhere anywhere tcp dpt:3000
ACCEPT tcp -- anywhere anywhere tcp dpt:https
ACCEPT tcp -- anywhere anywhere tcp dpt:http
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination

Answer 1

The error is because your firewall "iptables" blocked the port.
Rollback your iptables config, then issue the follow command:
iptables -I INPUT -i lo -p tcp --dport 3123 -j ACCEPT
Remember to save the setting by:
service iptables save
More information about iptables: https://help.ubuntu.com/community/IptablesHowTo
p.s. sudo may be needed for the above commands.