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Ahmed M Alzaeem

my router hanged & got down after configuring ipv6 ip on interface !!!!!

hi ,

i have virtual-templaet interfac e , and i  assigned an ipv6  pool to be assigned to users

i have:

#ipv6 local pool a1 2a03:ca40::/64 64

then under

virutal template interface

i have

#peer default ipv6 pool a1


after all of that , i go to inerface gi0/2  and put an ipv6 address from the pool above , then the router crashed !!!!!!!

here is the output of the crash

here is the crash that happedned :

*Jun 13 15:01:48.901: %ENTITY_ALARM-6-INFO: ASSERT CRITICAL Gi0/1 Physical Port Link Down


*Jun  13 15:01:48.905: %ADJ-3-ADJSTACK2: Adj stack2 error IPV6 midchain out  of Virtual-Access1509 (incomplete): cannot stack on linktype requested:  l2x session stack to destination for : ,  -Traceback= 0x1934118z  0x19349C8z 0x1934B48z 0x1933FC0z 0x1934E70z 0x190B4FCz 0x18A2974z  0x18BD1A0z 0x19094ECz 0x190522Cz 0x190614Cz 0x18BF76Cz 0x18BF910z  0x6CAB2Cz 0x7561F0z

the crash solved after reloading the router

i thought that the crash occured becuase of exceeding of virtual temaple ipv6 users that got ips from the pool

here is the output


LNS22#sh ipv6 local pool a1

Prefix is 2A03:CA40::/64 assign /128 prefix

6 entries in use, 0 rejected

121 entries cached, 1000 maximum

User                                                                     Prefix                                       Interface                                       

xxxx840@ng                                                      2A03:CA40::141B:456D:B86E:9991/128           Vi696                                           

xxxx484@ng                                                      2A03:CA40::9C3A:45C8:A5BB:AF2F/128           Vi344                                           

xxxx84@ng                                                      2A03:CA40::D963:3F04:6B85:88DC/128           Vi583                                           

xxxxxx777@ng                                                      2A03:CA40::E49F:FEAA:8F9A:468A/128           Vi613                                           

xxxx5679@ng                                                      2A03:CA40::F916:760F:5C6B:DA8B/128           Vi909

now i removed  assigning ipv6 addresses from virtual template ,

how to clear the ipv6 users above ???

i cant remove the pool a1 , it tell me  :

LNS2(config)#no ipv6 local pool a1 2A03:CA40::/64 128

% Pool cannot be removed when in use.

as u see, it tell me , it is in use !!!!

my request is ,

1-how to remove the ipv6 pool ????


2-how to remove the ipv6 virtual-access users ??????



Phillip Remaker
Cisco Employee

I'm sorry to hear about the crash, but what exactly is the crash?

What version software are you running (show version).

You should be able to disconnect users by clearing the interface, for example: clear interface vi696 should disocnnect user xxxx840@ng in the example above. 

Once you disconnect all users you should be able to remove the pool.

The %ADJ-3-ADJSTACK2 error is not a crash, and shouldn't have a serious negative impact.

I'd be more interested in helping you get the IPv6 working than disabling it!

Hi phillip ,

thanks for ur reply ,

actually , i cant clear the ipv6 users by the command =======> clear interface vi696

the command  above , only clear the ipv4 users , not the ipv6 users !!!!!


here is my ios & type :

i have router 7206 model ,

System image file is "disk2:c7200p-advipservicesk9-mz.124-24.T4.bin"

Cisco 7206VXR (NPE-G2) processor (revision A) with 917504K/65536K bytes of memory.

Processor board ID 26790100

MPC7448 CPU at 1666Mhz, Implementation 0, Rev 2.2

6 slot VXR midplane, Version 2.9


about the crash ,

the ios prevent me to put an ipv6 address from the pool range on the virtual-template interface ,

but when i put ipv6 address on another interface "Gi0/2" =======> the  router hanged and crashed and gave me the error:

*Jun  13 15:01:48.905: %ADJ-3-ADJSTACK2:  Adj stack2 error IPV6 midchain out  of Virtual-Access1509 (incomplete):  cannot stack on linktype requested:  l2x session stack to destination  for : ,  -Traceback= 0x1934118z  0x19349C8z 0x1934B48z 0x1933FC0z  0x1934E70z 0x190B4FCz 0x18A2974z  0x18BD1A0z 0x19094ECz 0x190522Cz  0x190614Cz 0x18BF76Cz 0x18BF910z  0x6CAB2Cz 0x7561F0z

wish 2 solve this issue , and  rem0ve & clear that annoying ipv6 pool !!

@phillip ,

This sounds like you may be up against some actual software bugs.  Perhaps you should open a case with the Cisco TAC on this one.

hi  phillip ,

could u tell me how to open a case with cisco tac ?