source: vendor/3.6.25/docs-xml/smbdotconf/protocol/maxprotocol.xml

<samba:parameter name="max protocol"
                 context="G"
                                 type="enum"
                 developer="1"
                 xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
<description>
    <para>The value of the parameter (a string) is the highest 
    protocol level that will be supported by the server.</para>

    <para>Possible values are :</para>
    <itemizedlist>
        <listitem>
            <para><constant>CORE</constant>: Earliest version. No 
            concept of user names.</para>
        </listitem>
                        
        <listitem>
            <para><constant>COREPLUS</constant>: Slight improvements on 
            CORE for efficiency.</para>
        </listitem>

        <listitem>
            <para><constant>LANMAN1</constant>: First <emphasis>
            modern</emphasis> version of the protocol. Long filename
            support.</para>
        </listitem>

        <listitem>
            <para><constant>LANMAN2</constant>: Updates to Lanman1 protocol.</para>
        </listitem>

        <listitem>
            <para><constant>NT1</constant>: Current up to date version of the protocol. 
            Used by Windows NT. Known as CIFS.</para>
        </listitem>
        <listitem>
            <para><constant>SMB2</constant>: Re-implementation of the SMB protocol.
            Used by Windows Vista and newer.</para>
        </listitem>
    </itemizedlist>

    <para>Normally this option should not be set as the automatic 
    negotiation phase in the SMB protocol takes care of choosing 
        the appropriate protocol.</para>
</description>

<related>min protocol</related>
<synonym>protocol</synonym>

<value type="default">NT1</value>
<value type="example">LANMAN1</value>
</samba:parameter>