asterisk users - Sep 2005 - Changing the sip port in sip.conf does not work

I can change the sip port to any number, and when I unload and reload
chan_sip.so, I always get
== Registered channel type 'SIP' (Session Initiation Protocol (SIP))
  == Parsing '/etc/asterisk/sip.conf': Found
  == SIP Listening on 64.1.16.172:5060
  == Using TOS bits 4
  == Parsing '/etc/asterisk/sip_notify.conf': Found
  == Registered application 'SIPDtmfMode'

Is there any other way to make the port change work? 
Also I never got an answer about how to prevent unregistered sip phones from
sending inbound SIP calls. I can send calls regardless if my softphone is
registered or not, when autocreatepeer=no. This is flaw that makes Asterisk
very insecure.
F.A.