[asterisk-users] Is 100 trying mandatory? Can asterisk answer with 180 without prior 100 trying?

[Daniel Tryba]

On Mon, Mar 19, 2018 at 12:59:47PM -0300, Joshua Colp wrote:
> > To try to reproduce the problem with our SBC, is there a way to tell
> > the asterisk, preferably PJSIP, to directly answer with 180 ringing
> > without prior 100 trying?
> 
> The PJSIP channel driver has no option or ability to do this. I do not recall if chan_sip does.

A (very) dirty workaround would be to drop these packets with iptables
(assuming Linux as OS), something like:

iptables -t raw -I OUTPUT -p udp -d ipaddrofpbx -m string --algo bm  --from 0 --to 32 --string "SIP/2.0 100 " -j DROP

Don't try it with TCP :)