title: Port Forwarding Not Working in CENT OS 6.5 for SQUID Transparent Proxy
body: <p>I am facing issues with Port forwarding in CENT OS 6.5.</p>
  
  <p>i need to forward all incoming traffic from port 80 to 3128. like setting up a transparent proxy server. what ever i tried it didn't worked. My Transparent proxy server IP is 10.5.255.252</p>
  
  <p>Please see my configuration below. </p>
  
  <pre><code>&lt;code&gt;
  [root@xxxxxxhost xx-yy]# iptables -t nat -L
  Chain PREROUTING (policy ACCEPT)
  target     prot opt source               destination         
  DNAT       tcp  --  anywhere             10.5.255.252        multiport dports http,https to:10.5.255.252:3128 
  
  Chain POSTROUTING (policy ACCEPT)
  target     prot opt source               destination         
  MASQUERADE  all  --  10.5.0.0/16          anywhere            
  
  Chain OUTPUT (policy ACCEPT)
  target     prot opt source               destination         
  
  [root@xxxxxxhost xx-yy]# iptables-save
  *nat
  :PREROUTING ACCEPT [18:3530]
  :POSTROUTING ACCEPT [9:540]
  :OUTPUT ACCEPT [228:14574]
  -A PREROUTING -d 10.5.255.252/32 -p tcp -m multiport --dports 80,443 -j DNAT --to-destination 10.5.255.252:3128 
  -A POSTROUTING -s 10.5.0.0/16 -o eth0 -j MASQUERADE 
  COMMIT
  
  [root@xxxxxxhost xx-yy]# cat /proc/sys/net/ipv4/ip_forward 
  1
  
  [root@xxxxxxhost xx-yy]# wget 127.0.0.1
  --2014-03-12 04:05:51--  http://127.0.0.1/
  Resolving 127.0.0.1... 127.0.0.1
  Connecting to 127.0.0.1|127.0.0.1|:80... failed: Connection refused.
  
  [root@xxxxxxhost xx-yy]# wget 127.0.0.1:3128
  --2014-03-12 04:05:55--  http://127.0.0.1:3128/
  Resolving 127.0.0.1... 127.0.0.1
  Connecting to 127.0.0.1|127.0.0.1|:3128... connected.
  HTTP request sent, awaiting response... ^C
  
  [root@xxxxxxhost xx-yy]# 
  &lt;/code&gt;
  </code></pre>
  
  <p>if you see above the wget request to localhost on port 80 is refused, but the request for 3128 port is accepted. so its not working :(</p>
  
  <p>Even tried the below rules.</p>
  
  <pre><code>&lt;code&gt;
  iptables -t nat -D PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 3128
  iptables -t nat -A PREROUTING -d 10.5.255.252 -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.5.255.252:3128
  iptables -t nat -A POSTROUTING -d 10.5.255.252 -p tcp --dport 3128 -j SNAT --to-source 10.5.255.252
  &lt;/code&gt;
  </code></pre>
  
  <p>But Nothing worked. Could you please help me to solve this.</p>
  
  <p>Appreciate your help.</p>