[asterisk-dev] Asterisk NAT Prolem

[Kevin P. Fleming]

Dome C. wrote:

>  >>Jan 20 00:00:20 WARNING[5473]: chan_sip.c:3424 process_sdp: Unable to 
> lookup host in c= line, 'IN IP4 >>203.156.4.2200'
>  >>Transmitting (NAT) to 203.156.4.220:17828:
>  >>SIP/2.0 488 Not acceptable here

The SDP coming from your device is broken. It's probably the 
firewall/NAT device mangling the SDP to put external IP addresses into 
it (which is not necessary, so turn it off).