# 4 Header and data length

#### Overview

Header and data length are present in response and request messages
between Zabbix components. It is required to determine the length of
message.

    <HEADER> - "ZBXD\x01" (5 bytes)
    <DATALEN> - data length (8 bytes). 1 will be formatted as 01/00/00/00/00/00/00/00 (eight bytes, 64 bit number in little-endian format)

To not exhaust memory (potentially) Zabbix protocol is limited to accept
only 128MB in one connection.