Thanks for the reply, Michael.
I tried the digest authentication using the cidr and copying the conf/sip_profiles/internal.xml from the distribution, where
<param name="apply-inbound-acl" value=”domains”/>
As a result, one endpoint could not register and another was unauthorized.
http://pastebin.freeswitch.org/11634
Then I went changed the context in internal.xml from public to default and
<param name="apply-inbound-acl" value="192.168.10.0/24"/> <param name="apply-register-acl" value="192.168.10.0/24"/>
And the phones registered OK. So my confusion persists.