4 Apr
2016
4 Apr
'16
11:12 p.m.
I am assuming you're adding Record-Route to your initial INVITEs?
If so, in the case of the answered call, it might be a defective UA that doesn't follow Record-Route for in-dialog messages (which include e2e ACK).
In the case of the negative replies, a scanner might not waste additional resources sending a formally requisite ACK. It'll just move on to the next target, and leave you holding the bag on the unacknowledged failed transaction.
-- Alex
--
Alex Balashov | Principal | Evariste Systems LLC
1447 Peachtree Street NE, Suite 700
Atlanta, GA 30309
United States
Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/