[Serusers] NAT keep-alive Was: Adding headers to the "200 OK" response

[Martin Koenig]

Hello all,

Wouldn't it make more sense to have an option send an OPTIONS request to the
NATed client? This would be a "real sip ping" rather than just an empty UDP
packet? Is this possible in either mediaproxy or rtpproxy?

What do you think?

Best regards,
Martin

> -----Original Message-----
> From: serusers-bounces at lists.iptel.org 
> [mailto:serusers-bounces at lists.iptel.org] On Behalf Of Kanakatti 
> Mahesh Subramanya
> Sent: Tuesday, November 30, 2004 7:01 AM
> To: serusers at lists.iptel.org
> Subject: [Serusers] Adding headers to the "200 OK" response
> 
> Is it possible to manipulate the "200 OK" response to a 
> REGISTER method?
> I need to add a header field to it, and as far as I can tell, there 
> really is no way to do this.
> 
> Why do I want to do this?
> Well, Snom foneslook for the presence of a "P-NAT-Refresh: 
> <yyyseconds>" 
> header in the "200 OK" response to their REGISTER methods. 
> If the header is present, the fones start sending out "keep-alive" 
> packets every yyy seconds, thus keeping NAT bindings open
> 
> Why dont I just use "natping_interval" in mediaproxy?
> Because there are a whole bunch of routers (linksys firewall/routers, 
> dlink ones, etc.) which only keep the binding open when there is a 
> packet sourced from the internal network.
> 
> Cheers
> 
>