I've come across an odd issue after just moving ISP's where my IPv6 traffic is bouncing up and down every 5 minutes. I've worked out it's linked to the IPv6 DHCP renewal that's taking place every 5 minutes but I don't know if it's setup error on my or their side? It wasn't occurring prior to the move this morning so logic says it's an issue on their side but I'd like to sanity check myself.
I see the following log entries when the IPv6 traffic works
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : wireguard_sync())
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : webgui_configure_do(,[wan,opt4]))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : vxlan_configure_do())
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : unbound_configure_do(,[wan,opt4]))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : openssh_configure_do(,[wan,opt4]))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : opendns_configure_do())
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : ntpd_configure_do())
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: miniupnpd: Starting service on interface: opt7, lan
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : miniupnpd_configure_do())
2026-02-05T13:37:50 Warning igmpproxy select() failure; Errno(4): Interrupted system call
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : igmpproxy_configure_do())
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : dhcrelay_configure_if(,[wan,opt4],inet6))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure newwanip (,[wan,opt4],inet6)
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure vpn (execute task : wireguard_configure_do())
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure vpn (execute task : openvpn_configure_do(,[wan,opt4]))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure vpn (execute task : ipsec_configure_do(,[wan,opt4]))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure vpn (,[wan,opt4],inet6)
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure monitor (execute task : dpinger_configure_do(,[WAN_DHCP6]))
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure monitor (,[WAN_DHCP6])
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: ROUTING: keeping inet6 default route to fe80::e65d:37ff:fe91:e88b%igc0
2026-02-05T13:37:50 Notice opnsense /usr/local/etc/rc.newwanipv6: ROUTING: configuring inet6 default gateway on wan
2026-02-05T13:37:49 Notice opnsense /usr/local/etc/rc.newwanipv6: ROUTING: entering configure using wan, opt4
2026-02-05T13:37:49 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure dhcp (execute task : radvd_configure_dhcp(,inet6))
2026-02-05T13:37:49 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure dhcp (execute task : dhcpd_dhcp_configure(,inet6))
2026-02-05T13:37:49 Notice opnsense /usr/local/etc/rc.newwanipv6: plugins_configure dhcp (,inet6)
2026-02-05T13:37:49 Notice opnsense /usr/local/etc/rc.newwanipv6: IP renewal starting (reason: request, address: fe80::baff:b3ff:fe06:6f1a%igc0, interface: wan, device: igc0)
2026-02-05T13:37:45 Notice dhcp6c got an expected reply, sleeping.
2026-02-05T13:37:45 Notice dhcp6c script "/var/etc/dhcp6c_wan_script.sh" terminated
2026-02-05T13:37:45 Notice dhcp6c dhcp6c_script: REQUEST on igc0 prefix now xxxx:xxxx:2938::/48
2026-02-05T13:37:45 Notice dhcp6c dhcp6c_script: REQUEST on igc0 connected to server
2026-02-05T13:37:45 Notice dhcp6c dhcp6c_script: REQUEST on igc0 executing
2026-02-05T13:37:45 Notice dhcp6c executes /var/etc/dhcp6c_wan_script.sh
2026-02-05T13:37:45 Notice dhcp6c removing server (ID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00)
2026-02-05T13:37:45 Notice dhcp6c removing an event on igc0, state=REQUEST
2026-02-05T13:37:45 Notice dhcp6c add an address xxxx:xxxx:xxxx:x:xxxx:xxxx:xxxx:1642/48 on vlan0.20
2026-02-05T13:37:45 Notice dhcp6c create a prefix xxxx:xxxx:2938::/48 pltime=600, vltime=600
2026-02-05T13:37:45 Notice dhcp6c make an IA: PD-0
2026-02-05T13:37:45 Notice dhcp6c Domain name server[1] 2a02:8010:6:0:212:23:6:100
2026-02-05T13:37:45 Notice dhcp6c Domain name server[0] 2a02:8010:6:0:212:23:3:100
2026-02-05T13:37:45 Notice dhcp6c Received REPLY for REQUEST
2026-02-05T13:37:45 Notice dhcp6c get DHCP option DNS, len 32
2026-02-05T13:37:45 Notice dhcp6c IA_PD prefix: xxxx:xxxx:xxxx::/48 pltime=600 vltime=600
2026-02-05T13:37:45 Notice dhcp6c get DHCP option IA_PD prefix, len 25
2026-02-05T13:37:45 Notice dhcp6c IA_PD: ID=0, T1=300, T2=480
2026-02-05T13:37:45 Notice dhcp6c get DHCP option IA_PD, len 41
2026-02-05T13:37:45 Notice dhcp6c DUID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00
2026-02-05T13:37:45 Notice dhcp6c get DHCP option server ID, len 26
2026-02-05T13:37:45 Notice dhcp6c DUID: 00:01:00:01:2f:04:80:83:60:be:b4:1e:16:40
2026-02-05T13:37:45 Notice dhcp6c get DHCP option client ID, len 14
2026-02-05T13:37:45 Notice dhcp6c receive reply from fe80::e65d:37ff:fe91:e88b%igc0 on igc0
2026-02-05T13:37:45 Notice dhcp6c reset a timer on igc0, state=REQUEST, timeo=0, retrans=1072
2026-02-05T13:37:45 Notice dhcp6c send request to ff02::1:2%igc0
2026-02-05T13:37:45 Notice dhcp6c set IA_PD
2026-02-05T13:37:45 Notice dhcp6c set IA_PD prefix
2026-02-05T13:37:45 Notice dhcp6c set option request (len 4)
2026-02-05T13:37:45 Notice dhcp6c set elapsed time (len 2)
2026-02-05T13:37:45 Notice dhcp6c set server ID (len 26)
2026-02-05T13:37:45 Notice dhcp6c set client ID (len 14)
2026-02-05T13:37:45 Notice dhcp6c a new XID (21be65) is generated
2026-02-05T13:37:45 Notice dhcp6c Sending Request on igc0
2026-02-05T13:37:45 Notice dhcp6c picked a server (ID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00)
2026-02-05T13:37:44 Notice dhcp6c reset timer for igc0 to 0.833093
2026-02-05T13:37:44 Notice dhcp6c server ID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00, pref=-1
2026-02-05T13:37:44 Notice dhcp6c get DHCP option DNS, len 32
2026-02-05T13:37:44 Notice dhcp6c IA_PD prefix: xxxx:xxxx:xxxx::/48 pltime=600 vltime=600
2026-02-05T13:37:44 Notice dhcp6c get DHCP option IA_PD prefix, len 25
2026-02-05T13:37:44 Notice dhcp6c IA_PD: ID=0, T1=300, T2=480
2026-02-05T13:37:44 Notice dhcp6c get DHCP option IA_PD, len 41
2026-02-05T13:37:44 Notice dhcp6c DUID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00
2026-02-05T13:37:44 Notice dhcp6c get DHCP option server ID, len 26
2026-02-05T13:37:44 Notice dhcp6c DUID: 00:01:00:01:2f:04:80:83:60:be:b4:1e:16:40
2026-02-05T13:37:44 Notice dhcp6c get DHCP option client ID, len 14
2026-02-05T13:37:44 Notice dhcp6c receive advertise from fe80::e65d:37ff:fe91:e88b%igc0 on igc0
2026-02-05T13:37:44 Notice dhcp6c reset a timer on igc0, state=SOLICIT, timeo=0, retrans=1021
2026-02-05T13:37:44 Notice dhcp6c send solicit to ff02::1:2%igc0
2026-02-05T13:37:44 Notice dhcp6c set IA_PD
2026-02-05T13:37:44 Notice dhcp6c set IA_PD prefix
2026-02-05T13:37:44 Notice dhcp6c set option request (len 4)
2026-02-05T13:37:44 Notice dhcp6c set elapsed time (len 2)
2026-02-05T13:37:44 Notice dhcp6c set client ID (len 14)
2026-02-05T13:37:44 Notice dhcp6c a new XID (231bfa) is generated
2026-02-05T13:37:44 Notice dhcp6c Sending Solicit on igc0
2026-02-05T13:37:43 Notice dhcp6c got an expected reply, sleeping.
2026-02-05T13:37:43 Notice dhcp6c script "/var/etc/dhcp6c_wan_script.sh" terminated
2026-02-05T13:37:43 Notice dhcp6c dhcp6c_script: RENEW on igc0 executing
2026-02-05T13:37:43 Notice dhcp6c executes /var/etc/dhcp6c_wan_script.sh
2026-02-05T13:37:43 Notice dhcp6c removing an event on igc0, state=RENEW
2026-02-05T13:37:43 Notice dhcp6c reset a timer on igc0, state=INIT, timeo=0, retrans=819
2026-02-05T13:37:43 Notice dhcp6c remove an IA: PD-0
2026-02-05T13:37:43 Notice dhcp6c IA PD-0 is invalidated
2026-02-05T13:37:43 Notice dhcp6c remove an address xxxx:xxxx:xxxx:x:xxxx:xxxx:xxxx:1642/48 on vlan0.20
2026-02-05T13:37:43 Notice dhcp6c remove a site prefix xxxx:xxxx:xxxx::/48
2026-02-05T13:37:43 Notice dhcp6c update a prefix xxxx:xxxx:xxxx::/48 pltime=0, vltime=0
2026-02-05T13:37:43 Notice dhcp6c update an IA: PD-0
2026-02-05T13:37:43 Notice dhcp6c Received REPLY for RENEW
2026-02-05T13:37:43 Notice dhcp6c status code: no binding
2026-02-05T13:37:43 Notice dhcp6c get DHCP option status code, len 29
2026-02-05T13:37:43 Notice dhcp6c IA_PD prefix: xxxx:xxxx:xxxx::/48 pltime=0 vltime=0
2026-02-05T13:37:43 Notice dhcp6c get DHCP option IA_PD prefix, len 58
2026-02-05T13:37:43 Notice dhcp6c IA_PD: ID=0, T1=0, T2=0
2026-02-05T13:37:43 Notice dhcp6c get DHCP option IA_PD, len 74
2026-02-05T13:37:43 Notice dhcp6c DUID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00
2026-02-05T13:37:43 Notice dhcp6c get DHCP option server ID, len 26
2026-02-05T13:37:43 Notice dhcp6c DUID: 00:01:00:01:2f:04:80:83:60:be:b4:1e:16:40
2026-02-05T13:37:43 Notice dhcp6c get DHCP option client ID, len 14
2026-02-05T13:37:43 Notice dhcp6c receive reply from fe80::e65d:37ff:fe91:e88b%igc0 on igc0
2026-02-05T13:37:43 Notice dhcp6c send renew to ff02::1:2%igc0
2026-02-05T13:37:43 Notice dhcp6c set IA_PD
2026-02-05T13:37:43 Notice dhcp6c set IA_PD prefix
2026-02-05T13:37:43 Notice dhcp6c set option request (len 4)
2026-02-05T13:37:43 Notice dhcp6c set elapsed time (len 2)
2026-02-05T13:37:43 Notice dhcp6c set server ID (len 26)
2026-02-05T13:37:43 Notice dhcp6c set client ID (len 14)
2026-02-05T13:37:43 Notice dhcp6c a new XID (f06898) is generated
2026-02-05T13:37:43 Notice dhcp6c Sending Renew on igc0
2026-02-05T13:37:43 Notice dhcp6c reset a timer on igc0, state=RENEW, timeo=0, retrans=10503
2026-02-05T13:37:43 Notice dhcp6c IA timeout for PD-0, state=ACTIVE
2026-02-05T13:37:30 Notice dhclient dhclient-script: Creating resolv.conf
2026-02-05T13:37:30 Notice dhclient dhclient-script: Reason RENEW on igc0 executing
After 5 mins the IPv6 DHCP renew occurs and it all stops working
2026-02-05T13:42:45 Notice dhcp6c got an expected reply, sleeping.
2026-02-05T13:42:45 Notice dhcp6c script "/var/etc/dhcp6c_wan_script.sh" terminated
2026-02-05T13:42:45 Notice dhcp6c dhcp6c_script: RENEW on igc0 executing
2026-02-05T13:42:45 Notice dhcp6c executes /var/etc/dhcp6c_wan_script.sh
2026-02-05T13:42:45 Notice dhcp6c removing an event on igc0, state=RENEW
2026-02-05T13:42:45 Notice dhcp6c add an address xxxx:xxxx:xxxx:x:xxxx:xxxx:xxxx:1642/48 on vlan0.20
2026-02-05T13:42:45 Notice dhcp6c update a prefix xxxx:xxxx:xxxx::/48 pltime=600, vltime=600
2026-02-05T13:42:45 Notice dhcp6c update an IA: PD-0
2026-02-05T13:42:45 Notice dhcp6c Domain name server[1] 2a02:8010:6:0:212:23:6:100
2026-02-05T13:42:45 Notice dhcp6c Domain name server[0] 2a02:8010:6:0:212:23:3:100
2026-02-05T13:42:45 Notice dhcp6c Received REPLY for RENEW
2026-02-05T13:42:45 Notice dhcp6c get DHCP option DNS, len 32
2026-02-05T13:42:45 Notice dhcp6c IA_PD prefix: xxxx:xxxx:xxxx::/48 pltime=600 vltime=600
2026-02-05T13:42:45 Notice dhcp6c get DHCP option IA_PD prefix, len 25
2026-02-05T13:42:45 Notice dhcp6c IA_PD: ID=0, T1=300, T2=480
2026-02-05T13:42:45 Notice dhcp6c get DHCP option IA_PD, len 41
2026-02-05T13:42:45 Notice dhcp6c DUID: 00:02:00:00:05:83:65:34:3a:35:64:3a:33:37:3a:39:31:3a:66:30:3a:36:34:00:00:00
2026-02-05T13:42:45 Notice dhcp6c get DHCP option server ID, len 26
2026-02-05T13:42:45 Notice dhcp6c DUID: 00:01:00:01:2f:04:80:83:60:be:b4:1e:16:40
2026-02-05T13:42:45 Notice dhcp6c get DHCP option client ID, len 14
2026-02-05T13:42:45 Notice dhcp6c receive reply from fe80::e65d:37ff:fe91:e88b%igc0 on igc0
2026-02-05T13:42:45 Notice dhcp6c send renew to ff02::1:2%igc0
2026-02-05T13:42:45 Notice dhcp6c set IA_PD
2026-02-05T13:42:45 Notice dhcp6c set IA_PD prefix
2026-02-05T13:42:45 Notice dhcp6c set option request (len 4)
2026-02-05T13:42:45 Notice dhcp6c set elapsed time (len 2)
2026-02-05T13:42:45 Notice dhcp6c set server ID (len 26)
2026-02-05T13:42:45 Notice dhcp6c set client ID (len 14)
2026-02-05T13:42:45 Notice dhcp6c a new XID (cae521) is generated
2026-02-05T13:42:45 Notice dhcp6c Sending Renew on igc0
2026-02-05T13:42:45 Notice dhcp6c reset a timer on igc0, state=RENEW, timeo=0, retrans=9493
2026-02-05T13:42:45 Notice dhcp6c IA timeout for PD-0, state=ACTIVE
2026-02-05T13:42:30 Notice dhclient dhclient-script: Creating resolv.conf
2026-02-05T13:42:30 Notice dhclient dhclient-script: Reason RENEW on igc0 executing
The process goes around in another 5 mins and traffic starts to flow again. I've logged the issue with my new ISP but I just wanted to know if there's anything on my side I'm not understanding?
> IA_PD prefix: xxxx:xxxx:xxxx::/48 pltime=600 vltime=600
Your ISP proposes a lifetime of 10 minutes. The client will honour it and try to renew the lease after 5 minutes.
Ask your ISP to set more conservative lifetime (pltime/vltime) defaults.
In theory we could add lifetime request values in the GUI but
1) nobody needed it so far
2) I'm not even sure it works reliably since the server has to decide
Cheers,
Franco
Thanks Franco, you've confirmed my thoughts and it's what I've requested back to my new ISP.