how to use IPv6 prefix-list !??

[mohammed hashim]

hi,

I ma trying to filter specific IPv6 prefix, but for some reason it did not work:

I want to filter only prefix 12::/64

R13#show run | s ipv6 pref
ipv6 prefix-list FILTER_IPV6 seq 10 deny 12::/64
ipv6 prefix-list FILTER_IPV6 seq 20 permit ::/0 le 32

R13#show run | s ipv6 router
ipv6 router ospf 100
distribute-list prefix-list FILTER_IPV6 in
default-information originate always

R13#show ipv6 route ospf
IPv6 Routing Table - default - 6 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE - Destination
NDr - Redirect, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
ls - LISP site, ld - LISP dyn-EID, a - Application
R13#

I tried to manipulate with the prefix, but did not help,

when I remove the prefix:

R13#show ipv6 route ospf
IPv6 Routing Table - default - 9 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE - Destination
NDr - Redirect, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
ls - LISP site, ld - LISP dyn-EID, a - Application
O 12::12/128 [110/1]
via FE80::250:56FF:FE92:6085, GigabitEthernet1.123
O 1212::1212/128 [110/1]
via FE80::250:56FF:FE92:6085, GigabitEthernet1.123
O EEEE::EE/128 [110/1]
via FE80::250:56FF:FE92:6085, GigabitEthernet1.123
R13#

so what is wrong in the config !?

[Jon Marshall]

What exactly is your question ?

You applied a filter that stopped all routes but when you removed the filter the specific prefix you want to filter is not in the routing table anyway.

So why are you trying to filter a prefix that isn't being received ?

Jon

[Peter Paluch]

Jon, Mohammed,

I believe I see the problem. The prefix list should have been specified as:

ipv6 prefix-list FILTER_IPV6 seq 10 deny 12::12/128
ipv6 prefix-list FILTER_IPV6 seq 20 permit ::/0 le 128

First of all, don't forget that IPv6 addresses have 128 bits, not 32. Second, if an exact network is to be matched then the prefix-list must match its prefix and prefix length exactly.

Best regards,
Peter

[Jon Marshall]

Peter

I agree the permit statement was wrong and based on an IPv4 prefix list, I just couldn't work out exactly what the question was because there was no sign of that route without the filter applied.

Jon

[Peter Paluch]

Jon,

Certainly - I am not suggesting that you have overlooked the solution. I just tried to extrapolate a little, and I decided to assume that perhaps not even the first entry was written correctly. The only network that resembled the 12::/64 was the 12::12/128, so I adapted the prefix-list for that.

Best regards,
Peter

[Jon Marshall]

Peter

Sorry, didn't mean it to come across in that way :)

Jon