How Can We Help?

OTT Upgrade – DHCP option 175

You are here:
< All Topics
Document Date and version2021.02.15
Tested with ONT HALNy HL-1GE, HL-1GE2, HL-4G, HL-4GMVSupported on Version: V2.0.13 or above
Tested with Ethernet Router HLE-4GMVSupported on Version: V2.0.18 or above
Tested with ONT HALNy HL-4GQV / HL-4GQVS / HL-4GQVS2 / HL-4GXV / HL-4GXV-FSupported on Version: V3.1.21p1 or above
Tested with Ethernet Router HLE-3GM / HLE-3GX-FSupported on Version: V3.1.21p1 or above
Let us know how to improve below document on:


  • if ONT receives DHCP OFFER packet with proper DHCP Option 175 to ip-host interface, next it downloads XML file with upgrade settings.
  • then ONT inspects downloaded XML file to check:
    1. At first, ONT checks EXCLUDED section
      • if there is ONT’s GPON/SN, then the upgrade process is ended
    2. ONT compares its active firmware version to firmware version in XML file
      • if firmware version is higher than active, then ONT downloads firmware file and upgrades itself
      • if firmware version is lower than active, then ONT checks DOWNGRADE_ENABLED flag
        • if that flag is set YES, then ONT will be downgraded
      • if firmware version is the same as standby, then ONT will switch to standby and reboot
  • after ONT downloads firmware or switch to standby, the next RELOAD_TIME is verified
  • ONT will reload itself according to time set in RELOAD_TIME flag

Topology and service scenario

Proper value of option 175

Option 175: IP address based on protocol:

  • for FTP (login credentials, ip address and port, XML file):
    • ftp://user:password@ (default port)
    • ftp://user:password@
    • (anonymous)
  • for FTPS (login credentials, ip address and port, XML file):
    • ftps://user:password@ (default port 990)
    • ftps://user:password@
    • ftps:// (anonymous)
  • for HTTP (contains IP address and port, XML file):
    • (default port)
  • for HTTPS (contains IP address and port, XML file):
    • (default port 443)

FTPS/HTTPS are supported from V2.0.21/V3.0.16

Name of .xml file (HALNy-upgrade.xml) does not matter

Example of upgrade XML

Link to upgrade xml example file: upgrade.xml

<?xml version="1.0"?>
<OTT version="1">

<FILENAME> path to the firmware file
<VERSION> firmware version to which ONT will be upgraded
<DOWNGRADE_ENABLED> if set to YES, ONT may download lower software version
<RELOAD TIME> ONT’s reload time, if upgrade succeeded
<EXCLUDED> ONTs with according GPON/SN won’t be upgraded.

No matter which OLT vendor ONT HALNY is connected to. ONT which is using OTT Upgrade may be upgraded just using DHCP Option 175.

Sample configuration of DHCP option 175 for Linux DHCP Server (isc-dhcp)

Installation isc-dhcp-server

Install isc-dhcp-server from debian/ubuntu repository

 $apt-get install isc-dhcp-server

Select default network interface for isc-dhcp-server

$nano /etc/default/isc-dhcp-server

 # Defaults for isc-dhcp-server (sourced by /etc/init.d/isc-dhcp-server)

 # Path to dhcpd's config file (default: /etc/dhcp/dhcpd.conf).

 # On what interfaces should the DHCP server (dhcpd) serve DHCP requests?
 #       Separate multiple interfaces with spaces, e.g. "eth0 eth1".

Simple isc-dhcp-server configuration with DHCP option 175

Edit isc-dhcp-serverconfig file

#definition of option code 175
option halny_upgrade code 175=text;

subnet netmask {
        option subnet-mask;
        option routers;
        option broadcast-address;
        option halny_upgrade "ftp://ftpuser:password123@";

Where is FTP server address.

Set static ip address of dhcp-server interface

$cat /etc/network/interfaces
auto enp0s3
iface enp0s3 inet static

Hardware-mask configuration

You can add option 175 only for HALNY ONT using hardware mask:
Edit isc-dhcp-server config file:


subnet netmask {
        option subnet-mask;
        option routers;
        option broadcast-address;
if substring(hardware, 1, 3) = e0:5a:9f {
	option halny_upgrade "ftp://ftpuser:password123@";

Mikrotik DHCP server configuration

DHCP server -> Add Option 175:

  1. Add new option
Obrazek posiada pusty atrybut alt; plik o nazwie Przechwytywanie2.png

Add values of option 175

Add created option to specific network (ONT iphost network space)

Table of Contents