Uses SIP to retrieve the local routing number information (LRN).

Requires IP Authentication to be setup through the portal and associated with LRN under Telco Data.

Send a SIP Invite to lrnlookup.telnyx.com with the number you wish to dip on port 5060. The response will be a SIP 302 redirect.

For example:

SIP/2.0 302 Moved Temporarily
Via: SIP/2.0/UDP 172.16.1.12;branch=z9hG4bKfae8cb69f547b8cb;received=172.16.0.179
From: <sip:5555555555@172.16.1.12>;tag=102
To: <sip:5555555555@174.36.199.131>
call-id: 0704037283648236478326200101@172.16.1.12
CSeq: 1 INVITE
Contact: Transfer <sip:5555555555;rn=+15555555556;npdi;@174.36.199.131>
Content-Length: 0

If a number has been ported the response will contain the dip indicator (npdi;) as well as the LRN (rn=+1..), otherwise these fields will be missing.