Hello all,
I have a SIP Trunk between my Asterisk and provider. When I try to outgoing call from tis trunk DTMF is work. But When incoming call from this trunk DTMF not work. Do you have any idea about this issuse My trunk description is:
disallow=all
type=peer
host=IP
allow=g722&alaw&ulaw&g729
transport=udp
context=from-trunk
canreinvite=yes
nat=no
qualify=yes
dtmfmode=info
relaxdtmf=yes
Have you confirmed with the provider what they use for DTMF? It’s uncommon to see info used as the method, usually it is rfc2833.
They say me “We use dtmf-relay rtp-nte sip-notify”. ingoing and outgoing call settings. They use Cisco VoIp gateway
Try setting dtmfmode=rfc2833 and seeing what happens.
I tried but nothing happend. And I tried auto,inband,info but it doesn’t work. 
I’m afraid those are the only options and if the Cisco equipment won’t negotiate or use any of them, then it seems as though DTMF will not work.
I think like you but when I try to test outgoing call on this trunk it work. therefore I can’t explain this sip provider.