Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

IPv6 - Turn Off Router Discovery

I have a Cisco AP 1262 running 15.2.4-JA1 which has IPv6 support.

I want to leave IPv6 neighbor discovery on but I want to disable router discovery so I can manually specify what default gateway to use.

You can do this on windows:

netsh inter ipv6 set interface XX routerdiscovery=disabled

I can't seem to find the command in IOS.

Thanks.

4 REPLIES
Cisco Employee

IPv6 - Turn Off Router Discovery

You do not have to do anything - by default IOS routers do not install the routes nor configure the interfaces in response to router advertisements.

if you want to do SLAAC, then you will configure "ipv6 address autoconfig", if you also want to

select default gateway based on RA, you will do "ipv6 address autoconfig default".

If you do not have this command, you will need to put all the routers manually or use a routing protocol.

New Member

IPv6 - Turn Off Router Discovery

On the contrary,

It seems my 1262 AP is doing this by default.

I did nothing but assign an IPv6 address to my AP and it was able to ping IPv6 Internet.

interface BVI1

ip address XXX.XXX.1.250 255.255.255.0

no ip route-cache

ipv6 address XXXX:XXXX:XXXX:1:FFFF:FFFF:FFFF:FFFA/64

ipv6 enable

ap#show ipv6 inter bvi1

BVI1 is up, line protocol is up

  IPv6 is enabled, link-local address is FE80::462B:3FF:FE91:XXXX

  No Virtual link-local address(es):

  Global unicast address(es):

    XXXX:XXXX:XXXX:1:FFFF:FFFF:FFFF:FFFA, subnet is XXXX:XXXX:XXXX:1::/64

  Joined group address(es):

    FF02::1

    FF02::1:FF91:3C8D

    FF02::1:FFFF:FFFA

  MTU is 1500 bytes

  ICMP error messages limited to one every 100 milliseconds

  ICMP redirects are enabled

  ICMP unreachables are sent

  ND DAD is enabled, number of DAD attempts: 1

  ND reachable time is 30000 milliseconds (using 30000)

  ND NS retransmit interval is 1000 milliseconds

  Default router is FE80::C2EA:E4FF:FE09:XXXX on BVI1

Cisco Employee

IPv6 - Turn Off Router Discovery

Ah, good point - seems like the ipv6 unicast-routing is off, and my claim indeed is incorrect for the host mode.

Several things to do:

A) just configure the ::/0 route with the appropriate interface/next hop - it will override the default which was obtained via received RA, even if the "sh ipv6 int X" will still show that.

B) make it a router, but disable all the RAs on the interface (I imagine you are bridging IPv6 to something else on the segment ?)

1) suppress all RAs on the BVI interface before enabling the routing: "ipv6 nd ra suppress all"

2) enable "ipv6 unicast-routing".

C) Alternatively, you can take care of this on the routers themselves by manipulating the lifetime - set it to zero on those that you do *not* wish to be selected as default router:

int X

ipv6 nd ra lifetime 0

This way you can affect the configuration on all the hosts at once.

--a

New Member

Re: IPv6 - Turn Off Router Discovery

Thanks Andrew.

I can't beleive Cisco does not have this option and M$ does.

Option A is my only choice.

Option B is not avaliable on my AP.

There is no command ipv6 nd ra suppress all

There is no command ipv6 unicast-routing

ap#config t
Enter configuration commands, one per line.  End with CNTL/Z.
ap(config)#inter bvi1
ap(config-if)#ipv6 nd ra suppress all
                             ^
% Invalid input detected at '^' marker.

ap(config-if)#end
ap#ipv6 unicast-routing
        ^
% Invalid input detected at '^' marker.

Option C is not really applicable for my topology becuase the AP is on a trunk port on a switch operating in L3 mode and the wireless clients still need the RA to access IPv6.

1538
Views
0
Helpful
4
Replies
CreatePlease login to create content