Permit Deny confusion with 1.6

I have an older server still running 1.6 and am a little confused about how the ACL permit/deny’s work in SIP.conf
Online docs seems to differ so I wonder if something has changed over versions.

eg is the command contactpermit= OR permit= ??? - I see examples using both

I want to issue a global deny, a couple of global allows and then user specific allows.

Testing so far is telling me that a global deny ( in [general]) does work but cannot be overridden in a user section so the only way I have got this to work is to repeat the lines in [general] below in each user section.
Is that really how it should be done?

Here is what I have that does not work ( denies the user-specific allows):


contactpermit= ; thid is my global allow

Secret=my pass
contactpermit= ; This does not work unless I comment out the [general] contactdeny



contactdeny/contactpermit is one of the less understood configuration options in chan_sip.
I asked about it a while ago and got no replies - viewtopic.php?t=80281
Most people simply stick with bare deny/permit and do not use the contactdeny/contactpermit options.