[asterisk-users] Empty SIP Packet

[Olle E. Johansson]

16 feb 2010 kl. 10.40 skrev Alexandru Oniciuc:

> Hello list,
>  
>                 debugging SIP, I found many empty lines like:
>  
> <--- SIP read from UDP://XXX.XXX.XXX.XXX:5060 --->
> <------------->
>  
>                 The IP address above corresponds to one of my accounts, which is behind a firewall.
>  
>                 Is that normal, maybe some firewall that tries to keep a port open, or is my firewall cleaning the SIP Packet?
>  
> Thanks in advance & best regards,
>  
It's one way of sending a SIP keepalive, many phones do this to keep NAT open.

/O