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
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 2001:4860:4860::8888
   name-server 2001:4860:4860::8844
   other-config-flag
   prefix 2001:DB8:beef:2::/64 {
       valid-lifetime 2592000
   }
   reachable-time 0
   retrans-timer 0
}