SIP RTP dynamic NAT

Hi:

I have a sip server running in my local network, my windows 2003 has 2
NIC's, external and internal and it routes traffic from the external do
internal NIC.

I need do register in my SIP server from the outside (accessing my networs
trhough external NIC), I can do that easy making a NAT on UDP 5060 but when
I try to make a call I can't ear audio because of the dynamic RTP ports wich
are established and define using SIP.

Is there a way of making an "intelligent SIP NAT" on windows 2003? It would
have to analyse sip requests and create a temp NAT for the RTP session.

Thanks,

Hugo

It requires a SIP Application Filter that does not exist in RRAS.

With commercial firewall products some have it,...and some don't. The newer
they are the better chance they have one.

SIP in a NAT environment is just simply a "bad deal". SIP was never
designed to operate across proxied, or NATed networks,...it was designed to
run over TCP/IP within a single LAN's administrative boundary (subnets are
fine). So now we have to deal with the SIP developer's short-sightedness.

The same thing is true of FTP,...but FTP Application Filters are more common
and the FTP design, although still a problem, is not quite as bad as SIP.


--
Phillip Windell
www.wandtv.com

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------


"Hugo" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi:
>
> I have a sip server running in my local network, my windows 2003 has 2
> NIC's, external and internal and it routes traffic from the external do
> internal NIC.
>
> I need do register in my SIP server from the outside (accessing my networs
> trhough external NIC), I can do that easy making a NAT on UDP 5060 but
> when I try to make a call I can't ear audio because of the dynamic RTP
> ports wich are established and define using SIP.
>
> Is there a way of making an "intelligent SIP NAT" on windows 2003? It
> would have to analyse sip requests and create a temp NAT for the RTP
> session.
>
> Thanks,
>
> Hugo
>

Thanks for the help!

Do you know any software solution for a windows 2003 without ISA server?

Thanks!

"Phillip Windell" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> It requires a SIP Application Filter that does not exist in RRAS.
>
> With commercial firewall products some have it,...and some don't. The
> newer they are the better chance they have one.
>
> SIP in a NAT environment is just simply a "bad deal". SIP was never
> designed to operate across proxied, or NATed networks,...it was designed
> to run over TCP/IP within a single LAN's administrative boundary (subnets
> are fine). So now we have to deal with the SIP developer's
> short-sightedness.
>
> The same thing is true of FTP,...but FTP Application Filters are more
> common and the FTP design, although still a problem, is not quite as bad
> as SIP.
>
>
> --
> Phillip Windell
> www.wandtv.com
>
> The views expressed, are my own and not those of my employer, or
> Microsoft,
> or anyone else associated with me, including my cats.
> -----------------------------------------------------
>
>
> "Hugo" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Hi:
>>
>> I have a sip server running in my local network, my windows 2003 has 2
>> NIC's, external and internal and it routes traffic from the external do
>> internal NIC.
>>
>> I need do register in my SIP server from the outside (accessing my
>> networs trhough external NIC), I can do that easy making a NAT on UDP
>> 5060 but when I try to make a call I can't ear audio because of the
>> dynamic RTP ports wich are established and define using SIP.
>>
>> Is there a way of making an "intelligent SIP NAT" on windows 2003? It
>> would have to analyse sip requests and create a temp NAT for the RTP
>> session.
>>
>> Thanks,
>>
>> Hugo
>>
>
>

"Hugo" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Thanks for the help!
>
> Do you know any software solution for a windows 2003 without ISA server?
>
> Thanks!

No sorry, I don't.
But maybe others here in these Groups may have some ideas.

There was only one third-party SIP App Filter for ISA and off the top of my
head I don't remember who it was.

Sometimes with SIP based VoIP solutions they come with their own
Router/Firewall device that is designed to handle what they are doing. Then
this device is just placed on the network edge (just like a firewall) and it
runs independently of any existing firewalls. Then it uses it's own Public
IP# over the same internet connection,...or it can use its own separate
dedicated internet connection.

--
Phillip Windell
www.wandtv.com

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------