[VoiceOps] Preventing random SIP connections to handsets

[Tim Bray]

On 20/11/15 22:57, Ryan Delgrosso wrote:
> 1: Stop using port 5060. Pick some other port for your phones to listen
> on locally. Do the same thing on your access-edge SBC's (this will also
> pay dividends in ALG avoidance).
> 2: Find the CPE option to restrict inbound to only the registered proxy.
> As mentioned before this might be different for each device make but it
> is unquestionably the best solution.

3. Some phones (like snom) expect invites with a line=xxxxx in the first 
line.   No line ID, no ringing.

INVITE sip:5060 at 192.168.2.174:35778;line=3vosp6yi SIP/2.0



-- 
Tim Bray
tim at kooky.org | +44 7966 479015 | http://www.kooky.org
Huddersfield, UK