sip_reg-4.1.0(1) on Linux
The text 3edcd3ff7c11, as Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it. The page shows this text now.
SIP Registration Agent
Flags it lists
-
--contact -
--from -
--proxy -
-c -
-r -
-u