/usr/share/doc/stun-server/nattestwarning.txt is in stun-server 0.97~dfsg-2.1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | WARNING: This script runs as "root" and makes changes to your network interface
configuration. This script makes several assumptions about the test environment
you might be using. Several of these assumptions may not hold in your environment
and could cause you to lose all connectivity to this or other computers.
It is designed to be run from the console on two networks which are connected
only to a NAT in a configuration like the one shown below:
Logical Configuration
+--------+
| STUN |192.168.0.2 +-------+
| Client |---------------| |
+--------+ | |public +--------+
| |side | STUN | 1.1.1.2
192.168.0.1 | NAT |------------| Server | 1.1.1.3
private side| |1.1.1.1 +--------+
| |
+--------+ | |
| STUN |---------------| |
| Client |192.168.0.3 +-------+
+--------+
The test actually just requires a single computer with two interfaces which acts
as a STUN server and a pair of cooperating STUN clients. The physical configuration
is shown below. First plug in the NAT and computer and configure the primary IP
interface on each interface. There should be no other computers or networks
connected to the test bed.
Physical Configuration
Private Public
or "inside" or "outside"
interface +--------------+ interface
| NAT device |
192.168.0.1 +-----| under |-----+ 1.1.1.1
| | test | |
| | | |
| +--------------+ |
| |
| |
| +--------------+ |
| | test | |
192.168.0.2 +-----| computer |-----+ 1.1.1.2
192.168.0.3 eth1| |eth0 1.1.1.3
| |
+--------------+
|