[Serusers] Firewall and NAT

Director General: NEFACOMP dg at nefacomp.net
Wed Jul 23 18:18:35 CEST 2003

I have got an H323 Mediatrix FXO gateway. It is not SIP based. May I use it
with SER?

----- Original Message -----
From: "Klaus Darilion" <darilion at ict.tuwien.ac.at>
To: "Rich Adamson" <radamson at routers.com>; <serusers at lists.iptel.org>
Sent: Wednesday, July 23, 2003 15:38
Subject: RE: [Serusers] Firewall and NAT

I think its this way:

FXO-interface: connects to the PSTN network an behaves like a normal phone
the PSTN network.

FXS-interface: connects to phone and behaves like a PSTN network to the
phone (acts as a power supply for the phone).

Simple scenario:

Analog Phone <---> FXS + PC <----VoIP----> PC + FXO (=Gateway) <---->PSTN


-----Original Message-----
From: Rich Adamson [mailto:radamson at routers.com]
Sent: Wed 23.07.2003 14:23
To: serusers at lists.iptel.org
Subject: Re: [Serusers] Firewall and NAT
> >We are using Check Point firewall I configured this
> >server to allow both way in/out and NATED with public
> >IP.
> >For testing purpose I kept all ports opened in the
> >firewall, for this particular server. I don’t why I am
> >not able to register it.

Might take a closer look at the Checkpoint to see if it is
doing Port Address Translation (PAT) in addition to NAT.
If I recall correctly, the older versions of Checkpoints
software did PAT, which caused folks problems when an app
wanted to use specific tcp/udp port numbers (for example,
when trying to use an non-checkpoint VPN box on the inside
of the checkpoint).

> >Which is better PSTN gateway. We are looking at 1 to 2
> >FXS port at this time for testing purpose.
> ? FXS is a PSTN-phone-2-IP gateway, isn't it? The most
> popular is cisco's ata.

Think the FXS is a Foreign Exchange interface intended to tie
a ser-accessible gateway to a telephone/pbx line (not to a
telephone instrument).

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