OPNsense Forum

English Forums => 26.1 Series => Topic started by: hakuna on February 12, 2026, 09:11:29 AM

Title: IPv6: OPNSense can ping, clients cannot. RA Identity association works.
Post by: hakuna on February 12, 2026, 09:11:29 AM
Hi all,

I finally got OPNSense to see my ISP IPv6, I had to change from IPoE back to PPPoE (ISP dramas).
OPNSense can ping IPv6 just fine but the clients cannot:

ping -6 2001:4860:4860::8888
From fe80::7e5a:1cff:fe48:1c50%eno1 icmp_seq=1 Destination unreachable: Beyond scope of source address


https://docs.opnsense.org/manual/radvd.html

Done that: If "Track Interface (legacy)" is used, an existing disabled entry will also deactivate advertisements on that interface. Alternatively, switch to "Identity association" for full manual configuration if needed."

Dnsmasq is disabled and not being used, and RA is not selected either

My PC network does show the 2400: IP under the DNS6 so it is seeing something.

ISC DHCPv6 service is disabled

Services > Router Advertisements:


Interfaces > LAN


Interfaces > WAN


OPNSense:
netstat -rn
Internet6:
Destination                       Gateway                       Flags         Netif Expire
default                           fe80::2293:39ff:fef6:75e3%pppoe0 UGS       pppoe0


ping6 -c 3 2001:4860:4860::8888
16 bytes from 2001:4860:4860::8888, icmp_seq=0 hlim=121 time=2.030 ms
16 bytes from 2001:4860:4860::8888, icmp_seq=1 hlim=121 time=1.957 ms
16 bytes from 2001:4860:4860::8888, icmp_seq=2 hlim=121 time=1.952 ms

I am running Unbound Recursive, no major changes other than "Register Mappings"

Thank you

Title: Re: IPv6: OPNSense can ping, clients cannot. RA Identity association works.
Post by: meyergru on February 12, 2026, 10:14:05 AM
It does not work like that (you already noticed, didn't you?).

Like with IPv4, there is two sides:

- WAN
- LAN

On WAN, you have to use whatever means it takes to get a WAN IP, often DHCPv4 and DHCPv6 as a client.

On LAN, you use DHCPv4 and (probably DHCPv6) as server. ALternatively, you can use SLAAC (RA) instead for IPv6.

You did neither: ISC DHCPv6, DNSmasq, RAdvd, all disabled. So how would clients get what they need. You must have IPv6 supplied to your LAN, otherwise it will not work.

There is a guide on how to do this via DNSmasq only in the official docs, instead, I prefer to do it like this (https://forum.opnsense.org/index.php?topic=45822.0).
Title: Re: IPv6: OPNSense can ping, clients cannot. RA Identity association works.
Post by: hakuna on February 12, 2026, 11:01:16 AM
Quote from: meyergru on Today at 10:14:05 AMIt does not work like that (you already noticed, didn't you?).

Like with IPv4, there is two sides:

- WAN
- LAN

On WAN, you have to use whatever means it takes to get a WAN IP, often DHCPv4 and DHCPv6 as a client.

On LAN, you use DHCPv4 and (probably DHCPv6) as server. ALternatively, you can use SLAAC (RA) instead for IPv6.

You did neither: ISC DHCPv6, DNSmasq, RAdvd, all disabled. So how would clients get what they need. You must have IPv6 supplied to your LAN, otherwise it will not work.

There is a guide on how to do this via DNSmasq only in the official docs, instead, I prefer to do it like this (https://forum.opnsense.org/index.php?topic=45822.0).


There seems to be a misunderstanding, let's try again :)


That is the main purpose of having LAN IPv6 > Tracks WAN > RA > Clients get out: things happen dynamically.
You should not have to set up a DHCPv6 server/pool manually and all, it must be fully dynamic.
Title: Re: IPv6: OPNSense can ping, clients cannot. RA Identity association works.
Post by: Boxer on February 12, 2026, 02:25:52 PM
Services > Router Advertisements:

    Interface: LAN
    Mode: *Unmanaged*
Title: Re: IPv6: OPNSense can ping, clients cannot. RA Identity association works.
Post by: meyergru on February 12, 2026, 02:46:30 PM
Correct: RA mode must be unmanaged for SLAAC. I only saw "RA is not selected either", so you use RADVD.