[SR-Users] Detecting calls with missing ACK (Lazy SIP scanners)

[Alex Balashov]

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/