by Justin Holcomb
Intentions
This guide is intended for those who run a Linux box as a router/firewall and want to run in active mode with DC++ behind the router/firewall. Although it is not limited to just DC++ but other applications and ports.
Short explanation
First I will explain the layout of the machines so you can apply it to your situation.
Your linux box has two network interfaces eth0 and eth1. eth0 is for your external internet connections and eth1 is for your internal connections. This example's eth0 address is 60.100.100.100 and the eth1 address is irrelavant for this guide. My windows computer that is running DC++ has a network address of 192.168.1.100.
Linux Instructions
Second on your linux box open a terminal emulator like xterm, aterm, gnome-terminal, etc. The enter the following commands:
iptables -t nat -A PREROUTING -p tcp -i eth0 -d 60.100.100.100 --dport 412 -j DNAT --to 192.168.1.100:412
iptables -A FORWARD -p tcp -i eth0 -d 60.100.100.100 --dport 412 -j ACCEPT
iptables -t nat -A PREROUTING -p udp -i eth0 -d 60.100.100.100 --dport 412 -j DNAT --to 192.168.1.100:412
iptables -A FORWARD -p udp -i eth0 -d 60.100.100.100 --dport 412 -j ACCEPT
These commands are case sensitive
IPTables is a packet filter for linux, also known as a firewall. The first line tells iptables to accept connections from eth0 coming in on port 412 to be send to 192.168.1.100, your DC++ client. The second line tells iptables to allow connections that have already been established to remain active. The third and fourth line are the same thing except for the UDP protocol.
Windows InstructionsStart DC++. Go to File > Settings...
Select the "Active" radio button under "Connection Settings..."
Change the IP to 60.100.100.100 and the port to 412
Click "OK" and connect to your favorite server.
Usefull Tip(s)
I don't know my external/internet IP address
If you are unsure what your external/internet ip address is your can go to and find out.
Thanks to...
Linus for creating the Linux kernel
If I forgot you please inform me.
Contact
Any questions/comments/suggestion can be sent to please_more_spam@yahoo.com. Yes it is my real email address, at least one of them. Or I can be contacted on AIM screenname "PolyPerception".
Do not post me (Mr.Grim) about this guide as i have no clue on anything related to Linux

Legal Notice
All copyrights and trademarks belong to their respective owners
This guide was last updated on: March 28, 2004