Complete Issabel Configs for MSTeams Direct Routing

Related to previous post about how to setup Issabel as Direct Routing SBC to MSTeams,I got requests from acquintances about the complete configurations from Issabel side.

So here they are:

sip_custom.conf (modify this from Asterisk File Editor webGUI)

[MSTeams-Inbound]
disallow=all
host=sip.pstnhub.microsoft.com
type=friend
transport=tls
port=5061
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-internal
insecure=port,invite
nat=force_rport,comedia
fromdomain=ast.ofon.biz

[MSTeams02-Inbound]
disallow=all
host=sip2.pstnhub.microsoft.com
type=friend
transport=tls
port=5061
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-internal
insecure=port,invite
nat=force_rport,comedia
fromdomain=ast.ofon.biz

[MSTeams03-Inbound]
disallow=all
host=sip3.pstnhub.microsoft.com
type=friend
transport=tls
port=5061
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-internal
insecure=port,invite
nat=force_rport,comedia
fromdomain=ast.ofon.biz

[Carrier-Inbound]
disallow=all
host=xxx.xxx.xxx.xxx
type=friend
port=xxxx
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-internal
insecure=port,invite
nat=force_rport,comedia

replace xxx are Carrier ip address, and port. replace fromdomain with your own FQDN Issabel server.

sip_additional.conf (modify this from Trunk webGUI menu)

[MSTeams-Outbound]
disallow=all
host=sip.pstnhub.microsoft.com
type=peer
transport=tls
port=5061
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-trunk
insecure=port,invite
nat=force_rport,comedia
fromdomain=ast.ofon.biz
encryption=yes

[MSTeams02-Outbound]
disallow=all
host=sip.pstnhub.microsoft.com
type=peer
transport=tls
port=5061
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-trunk
insecure=port,invite
nat=force_rport,comedia
fromdomain=ast.ofon.biz
encryption=yes

[MSTeams03-Outbound]
disallow=all
host=sip3.pstnhub.microsoft.com
type=peer
transport=tls
port=5061
allow=all
allow=ulaw
qualify=yes
dtmfmode=rfc2833
context=from-trunk
insecure=port,invite
nat=force_rport,comedia
fromdomain=ast.ofon.biz
encryption=yes

[Carrier-Outbound]
host=xxx.xxx.xxx.xxx
port=xxxx
canreinvite=yes
type=peer
insecure=port,invite
nat=force_rport,comedia
context=from-trunk
qualify=yes
dtmfmode=rfc2833

replace xxx are Carrier ip address, and port. replace fromdomain with your own FQDN Issabel server.

Outbound to MSTeams DID

I created 3 outbounds route with this order:

  • Outbound to MSTeams
  • Outbound to Carrier for REFER
  • Outbound to Carrier for each DID

The order should as such. And you dont need to setup any Inbound Routes.

Outbound route to MSTeams should contain your assigned DIDs toward MSTeams account. Should look like this:

Outbound Route to Accomodate REFER

Since I dont know how to replace user part of the URI with RPID, I just pick one DID to accomodate REFER. This is less desireable but the REFER outbound route can act as Global CallerID for the direct routing. Notice that the route contains disposable prefix 9 to avoid overriding from 3rd route (i.e Route for each DID).

This image has an empty alt attribute; its file name is image-2.png

Outbound Route to Carrier for Each DID

(extra) Asterisk SIP Settings from Unembedded IssabelPBX menu

Point the tlsprivatekey, tlscertfile, and tlscafile to your approriate files. And realm should be the Issabel server’s FQDN. The tlsbindaddr can by any ip address and port you wish to use.

That should do it. If I miss anything, please clue me at the comment.

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