slapd defaults to LDAPv3 but libldap defaults to LDAPv2 (ITS#1971)

[andrew.findlay@skills-1st.co.uk]

Full_Name: Andrew Findlay
Version: 2.1.3
OS: Linux Redhat 7.3
URL: 
Submission from: (NULL) (217.206.98.194)


The default setting for slapd is to accept only LDAP version 3.
However, the default for clients built with libldap is to request LDAP version
2.
This leads to the error message:
     ldap_bind: Protocol error (2)
          additional info: requested protocol version not allowed

The command-line tools are OK because they explicitly set the version, and have
their own default set to v3.

I suggest making ldap_int_initialize_global_options in libraries/libldap/init.c
set LDAP_VERSION3 as the default.

I also suggest adding a note to the Admin guide in the section on differences
between v2 and v3, pointing to the 'allow bind_v2' option so that users can
easily see how to enable backwards compatibility.

Programmers will need warning of the changed library behaviour. At the minimum,
a note on the default protocol version in ldap_init(3) should be added.