for example, you may check frame 9 in attachment

 

Frame 9 (105 bytes on wire, 105 bytes captured)
Ethernet II, Src: Microsof_85:ab:0c (00:03:ff:85:ab:0c), Dst: Microsof_a6:ab:0c (00:03:ff:a6:ab:0c)
Internet Protocol, Src: 10.10.12.1 (10.10.12.1), Dst: 10.5.3.1 (10.5.3.1)
Transmission Control Protocol, Src Port: 1543 (1543), Dst Port: ldap (389), Seq: 1, Ack: 1, Len: 51
Lightweight-Directory-Access-Protocol
    LDAPMessage searchRequest(4) "<ROOT>" baseObject
        messageID: 4
        protocolOp: searchRequest (3)
            searchRequest

<<<<<<<<<-----Base DN is missing here ---------->>>>>>>>>>>>>>
                scope: baseObject (0)
                derefAliases: neverDerefAliases (0)
                sizeLimit: 0
                timeLimit: 0
                typesOnly: False
                Filter: (objectClass=*)
                attributes: 0 items
        Response In: 11

 

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I found it a little bit diffcult to filter all ldap query with <root> base DN.