[Asterisk-Users] Re: Media Path Optimization & NAT

[Adam Sherman]

Rich Adamson wrote:
>>>>>>Now, I would very much like to remove the "canreinvite=no" from the 
>>>>>>provider's definition on sip.conf, but doing so causes Asterisk to send 
>>>>>>a re-invite to the provider pointing to a private IP. I thought that 
>>>>>>correct localnet entries would solve this...
>>>>>>
>>>>>
>>>>>By changing to canreinvite=yes, are you expecting the asterisk box to
>>>>>act as a router, passing rtp traffic from your sip provider through
>>>>>the box to a sip phone with a private address (without passing
>>>>>asterisk code in the middle of the rtp session)?
>>>>
>>>>No, sorry. I'm looking for Asterisk to not issue the re-invites if the 
>>>>two devices can't see each other. Think of mobile users who are often 
>>>>behind the corporate firewall but also travel. I'm trying to avoid 
>>>>having the media path be "user->corporate lan->pstn provider". I want it 
>>>>to be "user->pstn provider".
>>>>
>>>>If not to accomplish this, what are the localnet configuration entries for?
>>
>>>When a user is in the office, his phone registers with asterisk, and he
>>>places calls through asterisk to the sip provider. But, when he's
>>>out of the office, he takes his phone with him, and you are wanting
>>>him to make use of the canreinvite=yes to allow his phone to connect
>>>directly to the sip provider avoiding asterisk (from an rtp perspective). 
>>>Is that right?
>>
>>Yes. A softphone on a laptop makes for a more believable example though.
>>
>>So, is this possible? And, if not, what do the "localnet" entries provide?
> 
> I don't believe what you want is possible. The issue is in how sip
> handles reinvites and nating (or lack thereof). What will further
> complicate this is the laptop, when out of the office, is likely to
> be behind yet a different nat box and the addressing used behind
> that box may be completely different from your office nat.

In that case, what are the localnet configuration parameters for?

A.