To determine if it's behind a full-cone NAT, the client can send a
STUN Binding Request with flags that tell the STUN server to send a
response from a different IP address and port than the request was
received on. In other words, if the client sent a Binding Request to
IP address/port A/B using a source IP address/port of X/Y, the STUN
server would send the Binding Response to X/Y using source IP
address/port C/D. If the client receives this response, it knows it
is behind a full cone NAT.
I guess it isn't strictly required, but you won't be able to support all stun requests and nat topologies if only bound to 1 public IP.
On Wed, Nov 3, 2010 at 7:02 PM, Brian May
<brian@microcomaustralia.com.au> wrote:
On 4 November 2010 02:15, GillesToo <
codecomplete@free.fr> wrote:
> So I was wondering if Freeswitch could run as STUN server or if someone knew
> of a good open-source STUN server that I could install on the same host as
> the Freeswitch server?
scrooge:~# apt-cache show stun
Package: stun
Priority: optional
Section: net
Installed-Size: 176
Maintainer: Debian VoIP Team <pkg-voip-maintainers@lists.alioth.debian.org>
Architecture: i386
Version: 0.96.dfsg-5
Depends: libc6 (>= 2.6-1), libgcc1 (>= 1:4.2-20070516), libstdc++6 (>=
4.2-20070516)
Filename: pool/main/s/stun/stun_0.96.dfsg-5_i386.deb
Size: 41292
MD5sum: b8d9baaddbaf74016b6a0af3bdfd8545
SHA1: 8675d417af0e2d9076e91e46a82a99e3e728d45e
SHA256: ccb8fc9ad634b2ff98ebcc5d97eb2864df8a1c634109ef2fb641a7d2a2fb3a34
Description: Server daemon and test client for STUN
The STUN protocol (Simple Traversal of UDP through NATs) is described in the
IETF RFC 3489, available at http://www.ietf.org/rfc/rfc3489.txt. It's used to
help clients behind NAT to tunnel incoming calls through. This server is the
counterpart to help the client identify the NAT and have it open the proper
ports for it.
.
Homepage: http://www.vovida.org/applications/downloads/stun/
Tag: interface::commandline, interface::daemon,
network::{client,server,service,vpn}, protocol::{ip,udp,voip},
role::program, scope::utility, use::transmission
=== cut ===
Unfortunately the version in Debian/lenny seems to have this brain
dead assumption that you want it to bind to exactly two different IP
addresses (for increased reliability or something). I don't have any
additional public IPv4 addresses to spare.
At least that was the problem I encountered when I installed it
before. I might have been doing something wrong.
Also the home page mentioned above is useless.
--
Brian May <brian@microcomaustralia.com.au>
--
-Rupa