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Introduction

MAP-T (RFC 7599) is a stateless IPv4/IPv6 transition mechanism that enables IPv4 services over an IPv6-only network using algorithmic translation.

Translation happens at:

   MAP Customer Edge (CE): A device functioning as a Customer Edge
                           router in a MAP deployment.  A typical MAP CE
                           adopting MAP Rules will serve a residential
                           site with one WAN-side IPv6-addressed
                           interface and one or more LAN-side interfaces
                           addressed using private IPv4 addressing.

   MAP Border Relay (BR):  A MAP-enabled router managed by the service
                           provider at the edge of a MAP domain.  A BR
                           has at least an IPv6-enabled interface and an
                           IPv4 interface connected to the native IPv4
                           network.  A MAP BR may also be referred to as
                           simply a "BR" within the context of MAP.

MAP-T High-Level Architecture

MAPT Configuration

Customer Edge: Enable/Disable MAPT feature with below distro's from build

DISTRO_FEATURES_append = " feature_mapt"
DISTRO_FEATURES_append = " nat46"

Border Relay: Setup done in ubuntu machine ( linux kernel 5.15 )

Installation

sudo apt-get install isc-dhcp-server

Open file /etc/dhcp/dhcpd.conf and update as below

ddns-update-style none;
default-lease-time 3600;
max-lease-time 7200;
authoritative;
option custom-upstream-rate code 242 = unsigned integer 32;
option custom-downstream-rate code 243 = unsigned integer 32;

option domain-name "hsd.pa.crnrstn.comcast.net" ;

subnet 10.42.0.0 netmask 255.255.255.0 {
option routers 10.42.0.10;
option broadcast-address 10.42.0.255;
option domain-name-servers 1.1.1.1, 8.8.8.8;
range 10.42.0.3 10.42.0.254;

}

Open file /etc/radvd.conf
interface eth1 {
AdvSendAdvert on;
AdvManagedFlag on;
AdvOtherConfigFlag on;
prefix 2001:558:6013:100::/64 {
AdvOnLink on;
AdvAutonomous on;
};
};

Open file /etc/dhcp/dhcpd6.conf and update as below

ddns-update-style none;
default-lease-time 3600;
max-lease-time 7200;
option dhcp-renewal-time 1800;
option dhcp-rebinding-time 2880;
option client-class-information code 97 = string;
authoritative;
option dhcp6.map-option code 95 = string;
subnet6 2001:558:6013:0100::/64 {
range6 2001:558:6013:0100::1000 2001:558:6013:0100::1fff;
prefix6 2001:558:6013:0100:: 2001:558:6013:fe00:: /56;
option dhcp6.map-option 00:59:00:16:00:08:18:c0:a8:14:00:30:20:01:05:58:60:13:00:5d:00:04:08:08:00:00:00:5b:00:09:40:00:64:ff:9b:00:00:00:00;
option dhcp6.name-servers
2001:4860:4860::8888,
2001:4860:4860::8844;
}

Once all changes are done, restart the dhcpd and radvd service.

sudo systemctl restart isc-dhcp-server
sudo systemctl restart isc-dhcp-server6
sudo systemctl restart radvd

● isc-dhcp-server.service - ISC DHCP IPv4 server
     Loaded: loaded (/lib/systemd/system/isc-dhcp-server.service; disabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-04-06 15:22:33 IST; 135ms ago
       Docs: man:dhcpd(8)
   Main PID: 45322 (dhcpd)
      Tasks: 4 (limit: 18942)
     Memory: 4.6M
        CPU: 24ms
     CGroup: /system.slice/isc-dhcp-server.service
             └─45322 dhcpd -user dhcpd -group dhcpd -f -4 -pf /run/dhcp-server/dhcpd.pid -cf /etc/dhcp/dhcpd.conf eth1

Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: PID file: /run/dhcp-server/dhcpd.pid
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Wrote 3 leases to leases file.
Apr 06 15:22:33 CHTSL00399 sh[45322]: Wrote 3 leases to leases file.
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Listening on LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 sh[45322]: Listening on LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 sh[45322]: Sending on   LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 sh[45322]: Sending on   Socket/fallback/fallback-net
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Sending on   LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Sending on   Socket/fallback/fallback-net
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Server starting service.
● isc-dhcp-server6.service - ISC DHCP IPv6 server
     Loaded: loaded (/lib/systemd/system/isc-dhcp-server6.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-04-06 15:22:33 IST; 122ms ago
       Docs: man:dhcpd(8)
   Main PID: 45333 (dhcpd)
      Tasks: 4 (limit: 18942)
     Memory: 3.3M
        CPU: 18ms
     CGroup: /system.slice/isc-dhcp-server6.service
             └─45333 dhcpd -user dhcpd -group dhcpd -f -6 -pf /run/dhcp-server/dhcpd6.pid -cf /etc/dhcp/dhcpd6.conf eth1

Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: PID file: /run/dhcp-server/dhcpd6.pid
Apr 06 15:22:33 CHTSL00399 sh[45333]: Wrote 0 NA, 0 TA, 0 PD leases to lease file.
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Wrote 0 NA, 0 TA, 0 PD leases to lease file.
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Bound to *:547
Apr 06 15:22:33 CHTSL00399 sh[45333]: Bound to *:547
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Listening on Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 sh[45333]: Listening on Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 sh[45333]: Sending on   Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Sending on   Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Server starting service.
● radvd.service - Router advertisement daemon for IPv6
     Loaded: loaded (/lib/systemd/system/radvd.service; disabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-04-06 15:22:33 IST; 37ms ago
       Docs: man:radvd(8)
    Process: 45348 ExecStartPre=/usr/sbin/radvd --logmethod stderr_clean --configtest (code=exited, status=0/SUCCESS)
    Process: 45349 ExecStart=/usr/sbin/radvd --logmethod stderr_clean (code=exited, status=0/SUCCESS)
   Main PID: 45350 (radvd)
      Tasks: 2 (limit: 18942)
     Memory: 516.0K
        CPU: 64ms
     CGroup: /system.slice/radvd.service
             ├─45350 /usr/sbin/radvd --logmethod stderr_clean
             └─45351 /usr/sbin/radvd --logmethod stderr_clean

Apr 06 15:22:33 CHTSL00399 systemd[1]: Starting Router advertisement daemon for IPv6...
Apr 06 15:22:33 CHTSL00399 radvd[45348]: config file, /etc/radvd.conf, syntax ok
Apr 06 15:22:33 CHTSL00399 radvd[45349]: version 2.18 started
Apr 06 15:22:33 CHTSL00399 systemd[1]: Started Router advertisement daemon for IPv6.

Note: If using shared to other computers networkmanager will take care of sharing ipv4 and ipv6 internet. If using manual IP add required FORWARD rules in iptables.
To ping IPv6 add sudo ip6tables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

Jool Installation

Build the jool modules using below build instructions

sudo apt update
sudo apt upgrade
sudo apt install build-essential pkg-config
sudo wget https://github.com/NICMx/Jool/releases/download/v4.2.0-rc2/jool-4.2.0.rc2.tar.gz
sudo tar -xzf jool-4.2.0.rc2.tar.gz
sudo /sbin/dkms install jool-4.2.0.rc2/
cd jool-4.2.0.rc2/
sudo ./configure
sudo make
sudo make install

Once build completed, below modules will be generated in respective paths, add those modules to kernel path

ubuntu:~/jool-4.2.0~rc2$ find . -iname jool*ko
./src/mod/mapt/jool_mapt.ko
./src/mod/common/jool_common.ko
./src/mod/nat64/jool.ko
/src/mod/siit/jool_siit.ko

Jool configure

sudo modprobe jool_common
sudo modprobe jool_mapt
sudo modprobe jool

Enable below modules as well if not enabled
netfilter/nf_defrag_ipv4.ko
netfilter/nf_defrag_ipv6.ko

Once all modules are loaded and confirmed via lsmod

ubuntu:~/ lsmod | grep jool*
jool_mapt 20480 0
jool_common 253952 1 jool_mapt
nf_defrag_ipv6 24576 3 nf_conntrack,openvswitch,jool_mapt
nf_defrag_ipv4 16384 2 nf_conntrack,jool_mapt
x_tables 53248 9 xt_conntrack,nft_compat,xt_state,xt_tcpudp,xt_addrtype,xt_nat,ip_tables,xt_MASQUERADE,jool_mapt

Create an instance BR

sudo jool_mapt instance add "BR" --netfilter --dmr 64:ff9b::/64
sudo jool_mapt -i "BR" fmrt add 2001:558:6013::/48 192.168.20.0/24 8 8
sudo jool_mapt -i "BR" global update map-t-type BR

View the created instance using:

akhil@CHTSL00399:~$ sudo jool_mapt -i BR fmrt display
+---------------------------------------------+--------------------+----------------+----+
|                                 IPv6 Prefix |        IPv4 Prefix | EA-bits Length |  a |
+---------------------------------------------+--------------------+----------------+----+
|                         2001:558:6013::/48  |    192.168.20.0/24 | 16             |  6 |
+---------------------------------------------+--------------------+----------------+----+
akhil@CHTSL00399:~$ sudo jool_mapt instance display
+--------------------+-----------------+-----------+
|          Namespace |            Name | Framework |
+--------------------+-----------------+-----------+
|           89628c00 |              BR | netfilter |
+--------------------+-----------------+-----------+
akhil@CHTSL00399:~$

Enable dubbing for jool using sudo jool_mapt -i BR global update logging-debug true
cat /var/log/syslog

asas

Datamodels

root@Filogic-GW:~# dmcli eRT getv Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.
CR component name is: eRT.com.cisco.spvtg.ccsp.CR
subsystem_prefix eRT.
Execution succeed.
Parameter    1 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapTransportMode
               type:     string,    value: MAPT 
Parameter    2 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapBRPrefix
               type:     string,    value: 64:ff9b::/64 
Parameter    3 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapRuleIPv4Prefix
               type:     string,    value: 192.168.20.0 
Parameter    4 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapRuleIPv6Prefix
               type:     string,    value: 2001:558:6013::/48 
Parameter    5 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapEALen
               type:       uint,    value: 8 
Parameter    6 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapPSIDOffset
               type:       uint,    value: 8 
Parameter    7 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapPSIDLen
               type:       uint,    value: 8 
Parameter    8 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapPSID
               type:       uint,    value: 0 
Parameter    9 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapIsFMR
               type:       bool,    value: false 
Parameter   10 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapIpv4Address
               type:     string,    value: 192.168.20.254 
Parameter   11 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapRatio
               type:       uint,    value: 1