Assuming the following things you didn't lose a single word about but which are absolutely necessary to know (...), I'll try and give you some tips.
1. This is about Windows.
2. You want to use your home computer as a server.
3. You need to configure the NAT of an at&t router to let in packets to your bf server.
4. You need server manager for BF42 version 1.61b (or is it indeed 1.6?)
If this is correct, here are my tips:
- Donwload BFSM and BFRM
here.
- Start the server locally.
- Find all ports used by BF1942_w32ded.exe and BFServerManager.exe by typing "netstat -a -b -n" into a cmd console window. This will show you all listening UDP and TCP ports with the name of the respective process name.
- In your Windows Firewall / Other software firewall on your PC, open these ports.
- In your router, configure these ports to be forwarded to the IP adress of your PC. Since it uses
NAT, multiple internal LAN IP adresses are mapped to a single external internet IP adress. This means you need to tell your router which internal IP this packet on this port is for. Make sure, this is done correctly. I cannot find this setting for the internal LAN IP on your screenshot, maybe it's in "Summary" or "Advanced Settings". Should be an option for the "Application" where it asks you about the host this application is on ("ipconfig" in cmd to find out your LAN IP).
- Find out your internet IP in your router or
here and give it to the other players. Always remember that this could be a dynamic one and change every 24 hours (this is what it's like in Germany, could be static with your ISP in the US, though, idk).
- Do some research on the ports opened for BF and what they're good for. You won't need all of them, so after you found what exactly they do you might wanna close some of them again to improve the security of your home PC.
If you understood less than 80% of these tips, please consider seriously NOT TO HOST A SERVER AT ALL, since you could accidently expose your system to attacks / intrusions not knowing what you're doing.