Enabling DHCPv6 on WAN Interface causes constant reconnects

[Veksell]

I'm migrating from PFSense to OPNSense, Ive managed to get everything working except IPv6.

My ISP is IDNet they support IPv6 via DHCPv6 with a /48 prefix size using the IPv4 link connectivity which was working with PFSense.

When configuring just the PPPoE connection for IPv4 connectivity everything is working.

When I enable DHCPv6 on the WAN interface with a /48 prefix and selecting "Use IPv4 connectivity" it appears to briefly connect for a split second and then disconnect doing this repeatedly.

Looking at the PPP logs it is showing "LCP: parameter negotiation failed"

I have restarted OPNSense, restarted the ONT, confirmed theese were the same settings as before.

Here are the PPP logs from starting to stopping for a connection attempt:

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<30>1 2025-01-25T03:01:40+00:00 OPNsense ppp 53338 - [meta sequenceId="955"] [wan_link0] Link: reconnection attempt 1 in 4 seconds
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="956"] [wan_link0] Link: reconnection attempt 1
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="957"] [wan_link0] PPPoE: Set PPP-Max-Payload to '1500'
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="958"] [wan_link0] PPPoE: Connecting to ''
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="959"] PPPoE: rec'd ACNAME "BNG4.THN-LON-RE0"
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="960"] [wan_link0] PPPoE: rec'd PPP-Max-Payload '1500'
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="961"] [wan_link0] PPPoE: connection successful
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="962"] [wan_link0] Link: UP event
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="963"] [wan_link0] LCP: Up event
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="964"] [wan_link0] LCP: state change Starting --> Req-Sent
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="965"] [wan_link0] LCP: SendConfigReq #28
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="966"] [wan_link0]   PROTOCOMP
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="967"] [wan_link0]   MRU 1500
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="968"] [wan_link0]   MAGICNUM 0x8eca3cac
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="969"] [wan_link0] LCP: rec'd Configure Request #66 (Req-Sent)
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="970"] [wan_link0]   AUTHPROTO CHAP MD5
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="971"] [wan_link0]   MAGICNUM 0x0b0ec800
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="972"] [wan_link0] LCP: SendConfigAck #66
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="973"] [wan_link0]   AUTHPROTO CHAP MD5
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="974"] [wan_link0]   MAGICNUM 0x0b0ec800
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="975"] [wan_link0] LCP: state change Req-Sent --> Ack-Sent
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="976"] [wan_link0] LCP: rec'd Configure Ack #28 (Ack-Sent)
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="977"] [wan_link0]   PROTOCOMP
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="978"] [wan_link0]   MRU 1500
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="979"] [wan_link0]   MAGICNUM 0x8eca3cac
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="980"] [wan_link0] LCP: state change Ack-Sent --> Opened
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="981"] [wan_link0] LCP: auth: peer wants CHAP, I want nothing
<30>1 2025-01-25T03:01:44+00:00 OPNsense ppp 53338 - [meta sequenceId="982"] [wan_link0] LCP: LayerUp
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="983"] [wan_link0] CHAP: rec'd CHALLENGE #128 len: 37
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="984"] [wan_link0]   Name: "BNG4.THN-LON"
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="985"] [wan_link0] CHAP: Using authname "FTTP.**************@idnet"
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="986"] [wan_link0] CHAP: sending RESPONSE #128 len: 38
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="987"] [wan_link0] LCP: rec'd Configure Request #2 (Opened)
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="988"] [wan_link0]   MRU 1500
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="989"] [wan_link0]   AUTHPROTO CHAP MD5
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="990"] [wan_link0]   MAGICNUM 0x0b0ec800
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="991"] [wan_link0] LCP: LayerDown
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="992"] [wan_link0] LCP: parameter negotiation failed
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="993"] [wan_link0] LCP: state change Opened --> Stopping
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="994"] [wan_link0] LCP: SendTerminateReq #29
<30>1 2025-01-25T03:01:45+00:00 OPNsense ppp 53338 - [meta sequenceId="995"] [wan_link0] LCP: LayerDown

If anyone knows what might be the issue or what parameters it is failing to negotiate that would be very appreciated :)

[Veksell]

For Any one who might come across this issue and are having the same problem I ended up having to enable "Send prefix hint" on the WAN interface.