IPv6 SLAAC not reconnecting after modem drop



  • Ok, Now first I know there are a LOT of similar threads to this, but every one I have found is using DHCPv6 for the WAN, where I am using SLAAC.

    This morning my vdsl modem dropped off and reconnected.
    IPv4 came back fine.

    The only way to fix this is by rebooting the pfsense.

    Attached is the full log of my last 2 ppp connections.
    The first was on a fresh boot of the system, the more recent was the dropout we experienced this morning.
    The line that stands out to me is the following:
    Sep 23 09:05:29 ppp: [wan_link0] rec'd unexpected protocol IPv6

    The wierdest symptoms are ping responses from one of my windows clients trying to ping a host on the net.

    ipv4:

    C:\WINDOWS\system32>ping -4 tandyuk.com
    
    Pinging tandyuk.com [109.169.6.99] with 32 bytes of data:
    Reply from 109.169.6.99: bytes=32 time=11ms TTL=51
    Reply from 109.169.6.99: bytes=32 time=12ms TTL=51
    Reply from 109.169.6.99: bytes=32 time=11ms TTL=51
    Reply from 109.169.6.99: bytes=32 time=11ms TTL=51
    
    Ping statistics for 109.169.6.99:
        Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 11ms, Maximum = 12ms, Average = 11ms
    

    ipv6:

    C:\WINDOWS\system32>ping tandyuk.com
    
    Pinging tandyuk.com [2001:1b40:5000:22:1::85] with 32 bytes of data:
    Reply from 2001:1b40:5000:22:1::85: time<1ms
    Reply from 2001:1b40:5000:22:1::85: time<1ms
    Reply from 2001:1b40:5000:22:1::85: time=1ms
    Reply from 2001:1b40:5000:22:1::85: time<1ms
    
    Ping statistics for 2001:1b40:5000:22:1::85:
        Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 0ms, Maximum = 1ms, Average = 0ms
    

    The same v6 ping request from diagnostics > ping:

    PING6(56=40+8+8 bytes) 2001:4d48:ad53:2f00:1:: --> 2001:1b40:5000:22:1::85
    ping6: wrote tandyuk.com 16 chars, ret=-1
    ping6: wrote tandyuk.com 16 chars, ret=-1
    ping6: wrote tandyuk.com 16 chars, ret=-1
    
    --- tandyuk.com ping6 statistics ---
    3 packets transmitted, 0 packets received, 100.0% packet loss
    

    This causes numerous issues, as ipv6 sites appear to respond to pings, when in fact it is the pfsense that appears to be responding to the ping, rather than returning a network unreachable error.

    I will hold off rebooting the pfsense in case any other info is needed.
    pfsense-log-ppp.txt



  • Solved:

    System > Routing > Gateways > WAN_SLAAC >
    Check  Disable Gateway Monitoring

    Ipv6 all suddenly starts responding properly.