Bug #16398
open
When the PD of the WAN interface changes, DHCPv6 does not correctly send the Preferred Lifetime of the previous PD in the Router Advertisement, causing the client to not correctly update its Preferred IP address.
0%
Description
My ISP uses PPPoE+DHCPv6 to provide dual-stack capabilities. After redialing, the IPV6 prefix will change.
After the PD of the WAN interface was changed, pfsense was not correctly sending out router advertisements to list the previous IP address as non-preferred.
This will cause the Windows machine IPv6 under pfsense to be unable to connect to the Internet.
The attached file is the content of the router advertisement packet captured by Wireshark.
OpenWRT can handle this problem correctly.
It will invalidate the previous prefix and tell the client to use the new prefix, but pfsense does not tell the client that the previous prefix lifecycle has ended.
As a result, the newly sent prefix from pfsense is not listed as the preferred prefix, and Windows will continue to use the expired prefix.
Then I can't connect to the internet using ipv6.
After the PD update, Windows did not use 240e:38d:8dd8:a000 as the first choice, but continued to use the previous 240e:38d:88cc:5700.
ipconfig:
DHCP 已启用 . . . . . . . . . . . : 是
自动配置已启用. . . . . . . . . . : 是
IPv6 地址 . . . . . . . . . . . . : 240e:38d:88cc:5700:25a5:20a6:c3f5:758(首选)
IPv6 地址 . . . . . . . . . . . . : 240e:38d:8dd8:a000:4ca7:1dfe:b260:e491(首选)
IPv6 地址 . . . . . . . . . . . . : 240e:38d:8dd8:a000:a5d4:c49c:2bc5:da39(首选)
获得租约的时间 . . . . . . . . . : 2025年8月30日 22:41:57
租约过期的时间 . . . . . . . . . : 2025年8月30日 22:47:18
临时 IPv6 地址. . . . . . . . . . : 240e:38d:88cc:5700:5005:320d:4886:fd47(首选)
临时 IPv6 地址. . . . . . . . . . : 240e:38d:8dd8:a000:5005:320d:4886:fd47(首选)
本地链接 IPv6 地址. . . . . . . . : fe80::d79f:2a08:58e:c37c%16(首选)
IPv4 地址 . . . . . . . . . . . . : 192.168.1.101(首选)
子网掩码 . . . . . . . . . . . . : 255.255.255.0
获得租约的时间 . . . . . . . . . : 2025年8月30日 22:39:48
租约过期的时间 . . . . . . . . . : 2025年8月31日 0:39:47
默认网关. . . . . . . . . . . . . : fe80::92e2:baff:fe56:ed95%16
192.168.1.1
DHCP 服务器 . . . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 139253111
DHCPv6 客户端 DUID . . . . . . . : 00-01-00-01-2F-81-C9-E4-4C-D5-77-0A-91-A9
DNS 服务器 . . . . . . . . . . . : 240e:38d:8dd8:a000:92e2:baff:fe56:ed95
192.168.1.1
240e:38d:8dd8:a000:92e2:baff:fe56:ed95
240e:38d:88cc:5700:92e2:baff:fe56:ed95
TCPIP 上的 NetBIOS . . . . . . . : 已启用
Files
Updated by 
Updated by Kris Phillips 12 days ago
- Status changed from New to Confirmed
I can confirm this behavior. RAs should decrement the lifetime to 0 when upstream ISPs change prefix delegations in order to withdraw the routes.
However, this doesn't appear to be happening in 25.07.1. It's possible this has never happened and there was no hook for this.