[OpenSIPS-Users] Minimum SIP Headers

[Annus Fictus]

Hello,

on section 8.1.1 RFC 3261: " A valid SIP request formulated by a UAC 
MUST, at a minimum, contain the following header fields: To, From, CSeq, 
Call-ID, Max-Forwards,and Via;"

I'm sending to OpenSIPs a SIP INVITE (with SIPSAK) with these headers:

Via, From, To, Call-ID and Cseq (without Max-Forwars); OpenSIPs accept 
the message without problems. Is this the expected behavior?

Without other Header (between the six) the result is: 
ERROR:tm:t_lookup_request: too few headers

Thank you

Regards