Blocking Outbound NetBIOS

Microsoft Windows Networking uses a number of ports to communicate between servers and clients. Although SmoothWall GPL 1.0 blocks all inbound traffic on these ports by default, you may wish to block all outbound traffic on these ports. To block all outbound Microsoft Windows Networking traffic, add the following lines to /etc/rc.d/rc.firewall.up after the ipchains -N block statement. (Click here for more information on ssh, and click here for more information on editing files in SmoothWall.)
# RPC - Port 135
ipchains -A forward -p TCP -s 0/0 -d 0/0 135 -j REJECT
ipchains -A forward -p UDP -s 0/0 -d 0/0 135 -j REJECT
# NameService - Port 137, SMB datagram - Port138, session - Port 139
ipchains -A forward -p TCP -s 0/0 -d 0/0 137:139 -j REJECT
ipchains -A forward -p UDP -s 0/0 -d 0/0 137:139 -j REJECT
# Windows 2000 SMB - Port 445
ipchains -A forward -p TCP -s 0/0 -d 0/0 445 -j REJECT
ipchains -A forward -p UDP -s 0/0 -d 0/0 445 -j REJECT

For the above changes to take effect, you will need to reboot your SmoothWall GPL computer.

This page was last modified on 10 March, 2007.