login into the modem.......
aka (
http://192.168.1.1
username: admin password: admin)
if you get a web interface your problem is half solved........
if not then you need to telnet to 192.168.1.1 user admin/admin to login...
you will be provided with interface no worries more or less they are same...
look for NAT or Port triggering or port forwarding this kind of settings ......
You will eventually find it.... (mine comes under Advanced>NAT>add....) once you located it add any name... does matter azerus for instance assign a starting port... any take example 50001 and end port 50001 (In case you need to forward only one port) next setting will be for protocol (aka TCP or UDP or Both....... select Both) and last will be the connection you are using ptp over lan or bridge select whichever you are using most probably will be ptpoelan and save changes and an exception will be added to the router....
save and reboot the router aka( option will be there... just click it)
NOw you need to go in the preferences of the softwares... aka (azerus here for example and remove randomize everytime it starts and assign the port you just trigger aka(50001) and you will be done...
to save the above hassle you can use utorrent with unpn option it can forward any port (provided your isp supports it..), some minor speed will be lost but not noticeble...