Chci rozjet IPv6 na routeru (Linux Debian 12, FRR, včetně DHCPv6)

Zapnout IPv6 a forwarding

Poeditovat sysctl.conf

root@DB2-router1-debian12:~# nano /etc/sysctl.conf

Najít net.ipv6.conf.all.forwarding a nastavit 1. (projeví se po rebootu)

# Uncomment the next line to enable packet forwarding for IPv6
#  Enabling this option disables Stateless Address Autoconfiguration
#  based on Router Advertisements for this host
net.ipv6.conf.all.forwarding=1

Spustit sysctl (projeví se hned)

root@DB2-router1-debian12:~# sysctl net.ipv6.conf.all.forwarding=1

Kontrola (musí tam bejt 1)

root@DB2-router1-debian12:~# sysctl net.ipv6.conf.all.forwarding
net.ipv6.conf.all.forwarding = 1

Nastavit vlastní adresu pro router

Poeditovat /etc/network/interfaces

před (pouze IPv4)

po (oboje IPv4 a IPv6)

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# Spoj -> PMV, uplink
auto enp0s8
iface enp0s8 inet static
 address 10.107.99.130/30
  
# AP Oblast-DB2, router 1, tady jsou pripojenci
auto enp0s9
iface enp0s9 inet static
 address 10.107.185.1/26

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# Spoj -> PMV, uplink
auto enp0s8
iface enp0s8 inet static
 address 10.107.99.130/30
  
# AP Oblast-DB2, router 1, tady jsou pripojenci
auto enp0s9
iface enp0s9 inet static
 address 10.107.185.1/26
iface enp0s9 inet6 static
 address 2a01:16d:b210::/64

Na interface routeru doporučuji vždy nasazovat IPv6 adresu s prefixem /64 (pokud tam chcete adresovat více zařízení) nebo /128 (pokud vám stačí jen jedna adresa pro management). Vyvarujte se adresovat velké prefixy /40, /44 a /48 pokud vyloženě nevíte co děláte - přináší to problémy a nestandardní chování. Například nefunguje redistribute static apod.

Shodit a nahodit interface (bacha na ostrý síti!)

root@DB2-router1-debian12:~# ifdown enp0s9; ifup enp0s9

Kontrola

root@DB2-router1-debian12:~# ip address show

root@DB2-router1-debian12:~# ping6 2a01:16d:b210::

Routování - co budeme šířit ven?

Zadat 1x agregovanou routu pro tento router. Velikost bude mezi /40 - /48, záleží na správci. Doporučuju /44.

/etc/frr/daemons.conf

...
ospf6d=yes
...

/etc/frr/frr.conf

před (pouze IPv4)

po (oboje IPv4 a IPv6)

!
! Vzorovy router, oblast DB2, router 1
!
hostname DB2-router1-debian12
log syslog informational
frr defaults traditional

password free
enable password q7823yfbksldmf872fwfigu3ef97

! Verejky IPv4
ip route 89.200.202.0/28 eth0




interface enp0s8
 description Spoj -> PMV, uplink
 ip ospf cost 10
 ip ospf hello-interval 2
 ip ospf dead-interval 6






router ospf
 ospf router-id 10.107.185.1
 redistribute static

!
! Vzorovy router, oblast DB2, router 1
!
hostname DB2-router1-debian12
log syslog informational
frr defaults traditional

password free
enable password q7823yfbksldmf872fwfigu3ef97

! Verejky IPv4
ip route 89.200.202.0/28 eth0

! IPv6: Agregovana routa pro cely tento router (jde ven pres OSPF)
ipv6 route 2a01:16d:b210::/44 blackhole

interface enp0s8
 description Spoj -> PMV, uplink
 ip ospf cost 10
 ip ospf hello-interval 2
 ip ospf dead-interval 6
 ipv6 ospf6 area 0.0.0.0
 ipv6 ospf6 cost 10
 ipv6 ospf6 hello-interval 2
 ipv6 ospf6 dead-interval 6
 ipv6 ospf6 network point-to-point

router ospf
 ospf router-id 10.107.185.1
 redistribute static
 network 10.107.99.134/30 area 0.0.0.0

router ospf6
 ospf6 router-id 10.107.185.1
 redistribute static metric-type 1 route-map JEN-VELKY-SUBNETY

route-map JEN-VELKY-SUBNETY permit 10
  match ipv6 address prefix-list velikost-40-az-48

ipv6 prefix-list velikost-40-az-48 seq 5 permit 2a01:168::/29 ge 40 le 48

Kontrola na chybu v konfiguraci

root@DB2-router1-debian12:~# vtysh -C
root@DB2-router1-debian12:~#

žádnej výstup → je to OK

Restart FRR

root@DB2-router1-debian12:~# systemctl restart frr

Adresy pro připojence

Rozvaha

Ze subnetu 2a01:16d:b210::/44 (oblast DB2, router 1) si ukrojíme 2a01:16d:b120::/48 (oblast DB2, router 1, interface enp0s9).

Tento menší subnet rozdělíme na

2a01:16d:b210:0000::/56 - nepoužijeme
2a01:16d:b210:0100::/56 - pro připojence UID2350
2a01:16d:b210:0200::/56 - pro připojence UID2351
2a01:16d:b210:0300::/56 - pro připojence UID2352
2a01:16d:b210:0400::/56 - pro připojence UID2353

DHCPv6 server

Použijeme ne úplně mainstreamový dhcpy6d. Proč ne "běžné" DHCP servery? Protože chceme stejně jako v DHCPv4 indentifikovat klienty podle MAC adres. To v principu DHCPv6 neumí (umí pouze DUID). Tento dhcpy6d je jediný soft kde jsou MAC adresy (v rozporu s RFC) spolehlivě funkční (na Linuxu).

Běžné DHCPv6 servery:

dhcp6s - umí pouze DUID, neumí MAC

ISC DHCP - umí pouze DUID, navíc discontinued as of 2022

ISC Kea - pouze DUID, teoreticky umí MAC, prakticky špatně/nepoužitelně (mac-source metoda "raw" je popsaná ale není implementovaná, ostatní metody nespolehlivý)

Instalace

root@DB2-router1-debian12~# apt install dhcpy6d
root@DB2-router1-debian12~# apt install radvd
root@DB2-router1-debian12~# apt install sudo

root@DB2-router1-debian12:~# systemctl enable dhcpy6d

Poeditovat /etc/dhcpy6d.conf

# dhcpy6d configuration for hkfree.org
# 2023 VojtaLhota <vpithart@lhota.hkfree.org>
#
# Please see the examples in /usr/share/doc/dhcpy6d and https://dhcpy6.de/documentation for more information.
#
[dhcpy6d]
# Interface to listen to multicast ff02::1:2.
interface = enp0s9
really_do_it = yes

store_config = file
store_file_config = /etc/dhcpy6d-clients.conf

# SQLite DB for leases and LLIP-MAC-mapping.
store_volatile = sqlite
store_sqlite_volatile = /var/lib/dhcpy6d/volatile.sqlite
log = on
log_file = /var/log/dhcpy6d.log

manage_routes_at_start = yes

#
# Adresy a prefixy pro pripojence podle dhcpy6d-clients.conf
#
[class_valid_client]
advertise = addresses prefixes
addresses = hkfree_global_members
prefixes = hkfree_global_members
nameserver = 2a01:168:0:10::f:2 2a01:168:0:10::a
call_up = sudo ip -6 route add $prefix$/$length$ via $router$ dev enp0s9
call_down = sudo ip -6 route delete $prefix$/$length$ via $router$ dev enp0s9

[address_hkfree_global_members]
category = id
pattern = 2a01:16d:b210::$id$
preferred_lifetime = 86400
valid_lifetime = 86400

[prefix_hkfree_global_members]
category = id
pattern = 2a01:16d:b210:$id$::
length = 56
preferred_lifetime = 86400
valid_lifetime = 86400

#
# Nezname MAC adresy: dostanou adresu+prefix z rozsahu "f" na 3 minuty (max 5 minut)
#
[class_default]
advertise = addresses prefixes
addresses = hkfree_global_neznamy
prefixes = hkfree_global_neznamy
t1 = 180
t2 = 180
# tady zamerne neni call_up a call_down - neznama MAC adresa nebude mit routovani
# -> musi se spravne zadat do dhcpy6d-clients.conf, pak bude fungovat

[address_hkfree_global_neznamy]
category = range
range = fa00-ff00
pattern = 2a01:16d:b21f::$range$
preferred_lifetime = 180
valid_lifetime = 300

[prefix_hkfree_global_neznamy]
category = range
range = fa00-ff00
pattern = 2a01:16d:b21f:$range$::
length = 56
preferred_lifetime = 180
valid_lifetime = 300

Vytvořit /etc/dhcpy6d-clients.conf

# dhcpy6d configuration for hkfree.org
# 2023 VojtaLhota <vpithart@lhota.hkfree.org>
#
# 1 pripojenec = 1 zaznam
#
#  [uid2350]                   2350 - ID clena podle userdb
#  hostname = uid2350
#  mac = 08:00:27:1b:36:f9     MAC adresa klientskeho zarizeni clena
#  id = 0700                   0700 - cast adresy (bity 49-56), tj. v rozsahu 0100 - ff00
#  class = valid_client
#
#  [uid2351]                   2351 - ID clena podle userdb
#  hostname = uid2351
#  mac = 08:03:f3:22:33:54     MAC adresa klientskeho zarizeni clena
#  id = 7a00                   7a00 - cast adresy (bity 49-56), tj. v rozsahu 0100 - ff00
#  class = valid_client

[uid2350]
mac = 08:00:27:1b:36:f9
hostname = uid2350
id = 0100
class = valid_client


[uid2351]
mac = 08:00:37:dc:c6:23
hostname = uid2351
id = 0200
class = valid_client

Vytvořit /etc/sudoers.d/dhcpy6d-can-alter-ipv6-routes

# User dhcpy6d can add/remove ipv6 routes
dhcpy6d ALL=NOPASSWD: /usr/sbin/ip -6 route *

Vytvořit /etc/radvd.conf

interface enp0s9 {
  AdvSendAdvert on;
  AdvManagedFlag on;
	MinRtrAdvInterval 30;
	MaxRtrAdvInterval 300;
 	prefix 2a01:16d:b210::/64
	{
		AdvOnLink on;
		AdvAutonomous on;
		AdvRouterAddr off;
	};
};

(re)start DHCP serveru

root@DB2-router1-debian12:~# systemctl restart dhcpy6d

Logy s DHCP serveru:

root@DB2-router1-debian12:~# tail -f /var/log/dhcpy6d.log

Logy: Znamy klient (MAC 08:00:27:1b:36:f9) vyzaduje prefix

2023-12-17 16:04:17,425 dhcpy6d INFO SOLICIT | transaction: 4d469f | answer: normal | client_llip: fe80:0000:0000:0000:0a00:27ff:fe1b:36f9 | counter: 1 | duid: 000300010800270aef86 | ia_options: [25] | iaid: 00000002 | interface: enp0s9 | last_message_received_type: 1 | mac: 08:00:27:1b:36:f9 | options_request: [23] | rapid_commit: True
2023-12-17 16:04:17,426 dhcpy6d INFO REPLY | transaction: 4d469f | options: [7, 14, 23, 25]  | addresses: 2a01:016d:b210:0000:0000:0000:0000:0100 | client_class: valid_client | hostname: uid2350 | prefixes: 2a01:016d:b210:0100:0000:0000:0000:0000/56
2023-12-17 16:04:17,555 dhcpy6d INFO Called 'sudo ip -6 route add 2a01:016d:b210:0100:0000:0000:0000:0000/56 via 2a01:016d:b210:0000:0000:0000:0000:0100 dev enp0s9' to modify route - result: 0

Logy: znamy klient (MAC 08:00:27:1b:36:f9) vyzaduje prefix + adresu

2023-12-17 16:05:26,917 dhcpy6d INFO SOLICIT | transaction: 56026a | answer: normal | client_llip: fe80:0000:0000:0000:0a00:27ff:fe1b:36f9 | counter: 1 | duid: 000300010800270aef86 | ia_options: [3, 25] | iaid: 00000002 | interface: enp0s9 | last_message_received_type: 1 | mac: 08:00:27:1b:36:f9 | options_request: [23] | rapid_commit: True
2023-12-17 16:05:26,921 dhcpy6d INFO REPLY | transaction: 56026a | options: [3, 7, 14, 23, 25]  | addresses: 2a01:016d:b210:0000:0000:0000:0000:0100 | client_class: valid_client | hostname: uid2350 | prefixes: 2a01:016d:b210:0100:0000:0000:0000:0000/56
2023-12-17 16:05:27,092 dhcpy6d INFO Called 'sudo ip -6 route add 2a01:016d:b210:0100:0000:0000:0000:0000/56 via 2a01:016d:b210:0000:0000:0000:0000:0100 dev enp0s9' to modify route - result: 0

Logy: neznamy klient vyzaduje prefix + adresu → dostane "fa00" z odpadniho "f" rozsahu

2023-12-17 16:06:33,509 dhcpy6d INFO SOLICIT | transaction: 570ee2 | answer: normal | client_llip: fe80:0000:0000:0000:0a00:27ff:fe1b:36f0 | counter: 1 | duid: 000300010800270aefd8 | ia_options: [3, 25] | iaid: 00000002 | interface: enp0s9 | last_message_received_type: 1 | mac: 08:00:27:1b:36:f0 | options_request: [23] | rapid_commit: True
2023-12-17 16:06:33,510 dhcpy6d INFO REPLY | transaction: 570ee2 | options: [3, 7, 14, 25]  | addresses: 2a01:016d:b21f:0000:0000:0000:0000:fa00 | client_class: default_enp0s9 | prefixes: 2a01:016d:b21f:fa00:0000:0000:0000:0000/56

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