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

• wwan

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
}