[Blink] Blink only responding to some incoming calls

Andreas Sikkema ASikkema at office.unet.nl
Wed Jun 23 11:44:43 CEST 2010

> > I call on my cell phone to check if the number is working and Blink is
> > running and says available but more often then not it does not show 
> > a call is coming in.
> > I have not changed any of the default settings. Seems like there must 
> > one setting that is not right as sometimes the calls come in fine and 
> > can make calls out.
> Can you enable the SIP logging in the log window and paste what you see 
> when this happens? I haven't experienced this so I'd need some more 
> information in order to know what and why it's failing.

Are all Blink instances registered to the same server?

If yes, are all Blink instances behind a NAT?

If yes, are all Blink instances behind the same NAT?

if yes, are all Blink instances using the same port (5060) as the source 
port for their outgoing SIP traffic?

Most NAT implementations have lots of problems coping with the above 
situation, configure all Blink instances to use a different source port 
and I think all instances will start reliably receiving calls. I know it 
is counterintuitive and stupid and unneccesary and possibly the result of 
weird or buggy NAT implementations, but this is from very painful 

In the above situation the Blink instance that has last tried to renew its 
registration will receive all call attempts and only accept those that are 
meant for itself. 

BTW, this is not a Blink problem. ALL SIP clients behind the same NAT will 
probably experience this issue. Apart from the first client at the 
location all other SIP clients will need to be reconfigured.

Andreas Sikkema

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