*Important Note: It seems the -I INPUT 7 argument is confusing a lot of people. -I INPUT 7 was used in Daeson's case for the machine he was working on at the time, however this may not be the same for all machines. In Daeson's case there was a REJECT line in the INPUT CHAIN at line 8. So in order for us to get our port open we need to insert ie. -I into the INPUT CHAIN at line 7 before the REJECT line. On Machines with an INPUT CHAIN shorter then 7 lines this will cause an error. On machines without a REJECT line a simple "-A" appened aurgument can take the place of "-I INPUT 7". On a machine with a REJECT INPUT on a line before 8 you simply need to change the number to one smaller as long as it is before the REJECT line.

Argument -I is insert and -i is and network interface device and -p is protocol -s is source ipaddress and subnet, –dport is destination port and -j is rule.