I know that Kamailio works as a SIP Proxy and I also know that Asterisk/FreeSWITCH or other similar products can do what I'm asking here, but still wondering if it's possible to use Kamailio to answer a call or originate a call?
Let's say, "User ---> Kamailio", Kamailio answer the call with "200 OK to INVITE", and then play an announcement "Thank you for using Kamailio", then BYE the call?
I can't find any related information so I guess the answer is no, but still want to double check.
Many thanks in advance.
You can answer and play message if you use kamailio with mediaproxy.
Mediaproxy docs have some samples.
Originate is problematic and unreasonable in most cases, but there is https://www.kamailio.org/docs/modules/devel/modules/rtimer.html
Much simple method is use SIPP or perl/python sip module(external), after that rewrite call in kamailio as you wish.