Cleanup old IPv6 prefixes after daily VDSL reconnect

[numark]

Hello All,

i just got a VDSL connection with native IPv6 support. Everything works so far but my ISP forces my connection to reconnect every 24 hours.

The problem is that after a couple of reconnects, the dialer0 interface and all connected clients have multiple (old) IPv6 addresses as you can see below.

Is there a way to solve that issue ?

#show ipv6 interface dialer 0   

Dialer0 is up, line protocol is up

  IPv6 is enabled, link-local address is FE80::6600:F1FF:FE5F:2AC0 

  No Virtual link-local address(es):

  Stateless address autoconfig enabled

  Global unicast address(es):

    2001:16B8:500:F206:6600:F1FF:FE5F:2AC0, subnet is 2001:16B8:500:F206::/64 [EUI/CAL/DEP]

      valid lifetime 34345 preferred lifetime 0

    2001:16B8:503:53E1:6600:F1FF:FE5F:2AC0, subnet is 2001:16B8:503:53E1::/64 [EUI/CAL/DEP]

      valid lifetime 72915 preferred lifetime 0

    2001:16B8:1D01:56CC:6600:F1FF:FE5F:2AC0, subnet is 2001:16B8:1D01:56CC::/64 [EUI/CAL/PRE]

      valid lifetime 246048 preferred lifetime 159648

    2001:16B8:1D02:AC1A:6600:F1FF:FE5F:2AC0, subnet is 2001:16B8:1D02:AC1A::/64 [EUI/CAL/PRE]

      valid lifetime 258271 preferred lifetime 171871

    2001:16B8:1D03:2544:6600:F1FF:FE5F:2AC0, subnet is 2001:16B8:1D03:2544::/64 [EUI/CAL/DEP]

      valid lifetime 34596 preferred lifetime 0

    2001:16B8:1D03:EEA3:6600:F1FF:FE5F:2AC0, subnet is 2001:16B8:1D03:EEA3::/64 [EUI/CAL/PRE]

      valid lifetime 159065 preferred lifetime 72665

Thanks !

[Edwin Portillo]

Hi Friend,
Verify the valid life time of the IPv6 lease likewise the preferred duration time, for more reference, look at this post:

https://learningnetwork.cisco.com/thread/124273

[numark]

Thanks Edwin,

i already saw this article.I tried to limit the lifetime but it does not work as you can see below on the client.

sh run int dialer0

Building configuration...

Current configuration : 632 bytes

!

interface Dialer0

 encapsulation ppp

 dialer pool 1

 dialer-group 1

 ipv6 address autoconfig default

 ipv6 enable

 ipv6 nd ra suppress all

 ipv6 dhcp client pd hint ::/56

 ipv6 dhcp client pd prefix-from-provider rapid-commit

 ipv6 inspect v6inspect out

 ipv6 traffic-filter inbound in

 ppp authentication chap callin

 ppp chap hostname 

 ppp chap password 7 

show ipv6 general-prefix 

IPv6 Prefix prefix-from-provider, acquired via DHCP PD

  2001:16B8:1CF9:xxxx::/56 Valid lifetime 252062, preferred lifetime 165662

   BVI1 (Address command)

sh run int bvi1

Building configuration...

Current configuration : 308 bytes

!

interface BVI1

 ip address 10.0.0.254 255.255.255.0

 ip access-group 102 in

 ip nat inside

 ip virtual-reassembly in

 ip tcp adjust-mss 1412

 ipv6 address prefix-from-provider ::3:0:0:0:1/64

 ipv6 enable

 ipv6 nd prefix default 300 240

 ipv6 nd ra lifetime 300

Client:

ip -6 a

UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1

    inet6 ::1/128 scope host 

       valid_lft forever preferred_lft forever

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000

    inet6 2001:16b8:1cf9:xxxx:xxxx:32ff:fe88:5385/64 scope global mngtmpaddr dynamic 

       valid_lft 259077sec preferred_lft 172677sec

    inet6 fe80::211:32ff:fe88:5385/64 scope link 

       valid_lft forever preferred_lft forever