ルータにする

iptables のインストール

root@debian:~# apt-cache search iptables
iptables - administration tools for packet filtering and NAT
	:
	:
root@debian:~# apt-get install iptables
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  iptables
0 upgraded, 1 newly installed, 0 to remove and 9 not upgraded.
Need to get 550kB of archives.
After this operation, 1864kB of additional disk space will be used.
Get:1 http://ports.ubuntu.com jaunty/main iptables 1.4.1.1-4ubuntu3 [550kB]
Fetched 550kB in 2s (201kB/s)
Selecting previously deselected package iptables.
(Reading database ... 13103 files and directories currently installed.)
Unpacking iptables (from .../iptables_1.4.1.1-4ubuntu3_armel.deb) ...
Setting up iptables (1.4.1.1-4ubuntu3) ...

root@debian:~#

iptables の設定

具体的な設定を書くと、 そこを突かれる可能性があるので（＝設定に自信がないとも言う）

packet forwarding

	:
	:
# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1
	:
	:

外部からのテスト

内部からのテストは dnsmasq を入れてから。