LDAP authentication with just sAMAccountName

Hello,

I have a LDAP Linux  client written with OpenLDAP and i need it to be able to authenticate a user only by username and password (no domain). By username i mean the sAMAccountName from the LDAP record. The bind succeeds  if i use "username@domain" or if i use the userPrincipalName (which is not equal to  sAMAccountName), but i am unable to make it work just with username. Anonymous ldap_bind followed by a ldap_search does not work (it works if the bind is not anonymous).

I have also a windows client (not using openldap library) implemented with DirectoryEntry from C#. The login with just the username works fine in that implementation (connected to the same LDAP server). In the LDAP log file on Windows i see (i put [...] to hide the server address):

<Data Name="Message">ldap_bind called for connection 0xd059b718: DN is (null). Method is 0x486. Synchronous is 0x1.         <Data Name="Message">ldapBind found server is Windows 2003 or better AD on connection 0xd059b718         <Data Name="Message">Connection-&gt;hostname is &apos;[.........]&apos;         <Data Name="Message">Connection-&gt;DnsSuppliedNAme is &apos;[.........]&apos;         <Data Name="Message">Connection-&gt;DomainName is &apos;(null)&apos;         <Data Name="Message">LDAP: make spn returned &apos;ldap/[.........]&apos; with error 0         <Data Name="Message">ldapBind found GSSAPI auth type on connection 0xd059b718         <Data Name="Message">ldapBind found GSS-SPNEGO auth type on connection 0xd059b718         <Data Name="Message">ldapBind found DIGEST auth type on connection 0xd059b718         <Data Name="Message">ldap bind: Server is v3         <Data Name="Message">ldap bind: Server supports both GSS-SPNEGO and GSSAPI         <Data Name="Message">New servicename for bind is &apos;ldap/[.........]&apos;         <Data Name="Message">wldap32:Server is capable of &apos;NTLM&apos;         <Data Name="Message">ldap_bind returned 0x0 for connection 0xd059b718.

So on windows it does ldap_bind 2 times , but i think it is using a different mechanism, probably Windows specific (i mean not ldap_search) to retrieve the userPrincipalName associated with the sAMAccountName from input.

I do not have an account that i can use to make the initial bind (my client should work with several distinct servers). My question is: how to do it  on linux with OpenLDAP? Is it possible?

Thank you.