Router Advertisements

RAs are described in RFC 4861#section-4.6.2. They are part of what is known as SLAAC.

Supported interface types:

  • bonding

  • bridge

  • ethernet

  • l2tpv3

  • openvpn

  • pseudo-ethernet

  • tunnel

  • vxlan

  • wireguard

  • wireless

  • wirelessmodem

Enabling Advertisments

set service router-advert interface <interface> ….

Field

VyOS Option

Description

Cur Hop Limit

hop-limit

Hop count field of the outgoing RA packets

“Managed address configuration” flag

managed-flag

Tell hosts to use the administered stateful protocol (i.e. DHCP) for autoconfiguration

“Other configuration” flag

other-config-flag

Tell hosts to use the administered (stateful) protocol (i.e. DHCP) for autoconfiguration of other (non-address) information

MTU

link-mtu

Link MTU value placed in RAs, exluded in RAs if unset

Router Lifetime

default-lifetime

Lifetime associated with the default router in units of seconds

Reachable Time

reachable-time

Time, in milliseconds, that a node assumes a neighbor is reachable after having received a reachability confirmation

Retransmit Timer

retrans-timer

Time in milliseconds between retransmitted Neighbor Solicitation messages

Default Router Preference

default-preference

Preference associated with the default router

Interval

interval

Min and max intervals between unsolicited multicast RAs

DNSSL

dnssl

DNS search list to advertise

Name Server

name-server

Advertise DNS server per https://tools.ietf.org/html/rfc6106

Advertising a Prefix

set service router-advert interface <interface> prefix 2001:DB8::/32

VyOS Field

Description

decrement-lifetime

Lifetime is decremented by the number of seconds since the last RA - use in conjunction with a DHCPv6-PD prefix

deprecate-prefix

Upon shutdown, this option will deprecate the prefix by announcing it in the shutdown RA

no-autonomous-flag

Prefix can not be used for stateless address auto-configuration

no-on-link-flag

Prefix can not be used for on-link determination

preferred-lifetime

Time in seconds that the prefix will remain preferred (default 4 hours)

valid-lifetime

Time in seconds that the prefix will remain valid (default: 30 days)

Disabling Advertisements

To disable advertisements without deleting the configuration:

set service router-advert interface <interface> no-send-advert

Example Configuration

interface eth0.2 {
   default-preference high
   hop-limit 64
   interval {
       max 600
   }
   name-server 2001:db8::1
   name-server 2001:db8::2
   other-config-flag
   prefix 2001:db8:beef:2::/64 {
       valid-lifetime 2592000
   }
   reachable-time 0
   retrans-timer 0
}