Tuesday, November 14, 2017

Providing DNSv6 server info via ISG

 Here we are trying to assign IPv6 address using SLAAC and send DNS v6 server info using DHCPv6.
   
  For this we have to confogure a IPv6 local pool in ISG as show below:
   
  ipv6 local pool RED 6868::/48 64
   
  First, configure the ISG as DHCPv6 server by defining a IPv6 pool
   
 
   ASR-2#show run | s POOL14
 
   ipv6 dhcp pool POOL14
 
    dns-server 1818::1818
 
    
 
   ##################################################
 
    
 
   Now add the below commands to the access interface config:
   
  ASR-2#show run int g1/2/1.200
  Building configuration...
   
  Current configuration : 279 bytes
  !
  interface GigabitEthernet1/2/1.200
   encapsulation dot1Q 200
   ip unnumbered Loopback66
   ipv6 enable
   ipv6 nd other-config-flag    <<<<<<<<<
   ipv6 dhcp server POOL14    <<<<<<<<<<
   service-policy type control START_MAC
   ip subscriber l2-connected
    initiator unclassified mac-address
    initiator dhcp
  end
   
  ASR-2#
  ASR-2#
  ASR-2#
   
  Enable below debugs:
   

 
   ASR-2#debug ipv6 dhcp detail 
 
      IPv6 DHCP debugging is on (detailed)
 
   ASR-2#
 
   ASR-2#
 
   ASR-2#
 
   ASR-2#config t
 
   Enter configuration commands, one per line.  End with CNTL/Z.
 
   ASR-2(config)#logg conso
 
   ASR-2(config)#^Z
 
   ASR-2#
 
   ASR-2#
 
   ASR-2#
 
   ASR-2#sss
 
   %No active Subscriber Sessions
 
   ASR-2#
 
   *Aug 22 08:58:21.455 IST: %SYS-5-CONFIG_I: Configured from console by console
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP: Received INFORMATION-REQUEST from FE80::201:11FF:FE11:2222 on GigabitEthernet1/2/2.500
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP: detailed packet contents
 
   *Aug 22 08:58:37.406 IST:   src FE80::201:11FF:FE11:2222 (GigabitEthernet1/2/2.500)
 
   *Aug 22 08:58:37.406 IST:   dst FF02::1:2
 
   *Aug 22 08:58:37.406 IST:   type INFORMATION-REQUEST(11), xid 7260385
 
   *Aug 22 08:58:37.406 IST:   option ELAPSED-TIME(8), len 2
 
   *Aug 22 08:58:37.406 IST:     elapsed-time 0
 
   *Aug 22 08:58:37.406 IST:   option CLIENTID(1), len 10
 
   *Aug 22 08:58:37.406 IST:     00030001442B035DFF80
 
   *Aug 22 08:58:37.406 IST:   option ORO(6), len 6
 
   *Aug 22 08:58:37.406 IST:     DNS-SERVERS,DOMAIN-LIST,UNKNOWN
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP: Using interface pool POOL14
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP_AAA: Retrieved subblock; It has AAA DNS_SERVERS=0
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP: Source Address from SAS FE80::227:DFF:FE4E:D562
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP: detailed packet contents
 
   *Aug 22 08:58:37.406 IST:   src FE80::227:DFF:FE4E:D562
 
   *Aug 22 08:58:37.406 IST:   dst FE80::201:11FF:FE11:2222 (GigabitEthernet1/2/2.500)
 
   *Aug 22 08:58:37.406 IST:   type REPLY(7), xid 7260385
 
   *Aug 22 08:58:37.406 IST:   option SERVERID(2), len 10
 
   *Aug 22 08:58:37.406 IST:     0003000100270D4ED500
 
   *Aug 22 08:58:37.406 IST:   option CLIENTID(1), len 10
 
   *Aug 22 08:58:37.406 IST:     00030001442B035DFF80
 
   *Aug 22 08:58:37.406 IST:   option DNS-SERVERS(23), len 16
 
   *Aug 22 08:58:37.406 IST:     1818::1818
 
   *Aug 22 08:58:37.406 IST: IPv6 DHCP: Sending REPLY to FE80::201:11FF:FE11:2222 on GigabitEthernet1/2/2.500
 
   ASR-2#
 
    
 
    
 
   ####################################################################################
 
    
 
   Enable below debug in client:
 
    
 
  
    client#debug ipv6 dhcp detail  
  
       IPv6 DHCP debugging is on (detailed) 
  
    client# 
  
    client# 
  
    client#config t 
  
    Enter configuration commands, one per line.  End with CNTL/Z. 
  
    client(config)#int g0/2.500 
  
    client(config-subif)#shut 
  
      
  
    *Aug 22 15:55:55.767: IPv6 DHCP: Stopping client stateless autoconfig 
  
    *Aug 22 15:55:55.767: IPv6 DHCP: Unconfiguring DNS server 1818::1818 
  
    client(config-subif)# 
  
    client(config-subif)# 
  
    client(config-subif)# 
  
    client(config-subif)#no shut 
  
    client(config-subif)# 
  
    *Aug 22 15:56:05.379:  DEBUG_SWITCH:ARP 64.64.64.3 64.64.64.1 
  
    *Aug 22 15:56:05.379:  DEBUG_SWITCH:OFP Roaming 64.64.64.1 observed 
  
    *Aug 22 15:56:07.383: IPv6 DHCP: Sending INFORMATION-REQUEST to FF02::1:2 on GigabitEthernet0/2.500 
  
    *Aug 22 15:56:07.383: IPv6 DHCP: detailed packet contents 
  
    *Aug 22 15:56:07.383:   src FE80::201:11FF:FE11:2222 
  
    *Aug 22 15:56:07.383:   dst FF02::1:2 (GigabitEthernet0/2.500) 
  
    *Aug 22 15:56:07.383:   type INFORMATION-REQUEST(11), xid 7387384 
  
    *Aug 22 15:56:07.383:   option ELAPSED-TIME(8), len 2 
  
    *Aug 22 15:56:07.383:     elapsed-time 0 
  
    *Aug 22 15:56:07.383:   option CLIENTID(1), len 10 
  
    *Aug 22 15:56:07.383:     00030001442B035DFF80 
  
    *Aug 22 15:56:07.383:   option ORO(6), len 6 
  
    *Aug 22 15:56:07.383:     DNS-SERVERS,DOMAIN-LIST,INFO-REFRESH 
  
    *Aug 22 15:56:07.383: IPv6 DHCP: DHCPv6 changes state from IDLE to INFORMATION-REQUEST (STATELESS) on GigabitEthernet0/2.500 
  
    *Aug 22 15:56:07.385: IPv6 DHCP: Received REPLY from FE80::227:DFF:FE4E:D562 on GigabitEthernet0/2.500 
  
    *Aug 22 15:56:07.385: IPv6 DHCP: detailed packet contents 
  
    *Aug 22 15:56:07.385:   src FE80::227:DFF:FE4E:D562 (GigabitEthernet0/2.500) 
  
    *Aug 22 15:56:07.385:   dst FE80::201:11FF:FE11:2222 (GigabitEthernet0/2.500) 
  
    *Aug 22 15:56:07.385:   type REPLY(7), xid 7387384 
  
    *Aug 22 15:56:07.385:   option SERVERID(2), len 10 
  
    *Aug 22 15:56:07.385:     0003000100270D4ED500 
  
    *Aug 22 15:56:07.385:   option CLIENTID(1), len 10 
  
    *Aug 22 15:56:07.385:     00030001442B035DFF80 
  
    *Aug 22 15:56:07.385:   option DNS-SERVERS(23), len 16 
  
    *Aug 22 15:56:07.385:     1818::1818 
  
    *Aug 22 15:56:07.385: IPv6 DHCP: Adding server FE80::227:DFF:FE4E:D562 
  
    *Aug 22 15:56:07.385: IPv6 DHCP: Processing options 
  
    *   Aug 22 15:56:07.385: IPv6 DHCP: Configuring DNS server 1818::1818     <<<<<<<<<< 
  
    *Aug 22 15:56:07.385: IPv6 DHCP: DHCPv6 changes state from INFORMATION-REQUEST to IDLE (REPLY_RECEIVED) on GigabitEthernet0/2.500 
  
    client(config-subif)# 
  
    client(config-subif)# 
  
    client(config-subif)# 
  
    *Aug 22 15:56:10.385:  DEBUG_SWITCH:ARP 64.64.64.3 64.64.64.1 
  
    *Aug 22 15:56:10.385:  DEBUG_SWITCH:OFP Roaming 64.64.64.1 observed 
  
    *Aug 22 15:56:11.427: %DHCP-6-ADDRESS_ASSIGN: Interface GigabitEthernet0/2.500 assigned DHCP address 64.64.64.3, mask 255.255.255.0, hostname client 
  
      
  
    client(config-subif)# 
  
    client(config-subif)# 
  
      
  
    Use the below command to view the DNS info received: 
  
      
  
   
     client#show ipv6 dhcp interface g0/2.500  
   
     GigabitEthernet0/2.500 is in client mode  
   
       Prefix State is IDLE (0)  
   
       Information refresh timer expires in 23:53:18  
   
       Address State is IDLE  
   
       List of known servers:  
   
         Reachable via address: FE80::227:DFF:FE4E:D562  
   
         DUID: 0003000100270D4ED500  
   
         Preference: 0  
   
         Configuration parameters:  
   
           DNS server: 1818::1818   <<<<<<<<<<<<<<<<<<  
   
           Information refresh time: 0  
   
       Prefix Rapid-Commit: disabled  
   
       Address Rapid-Commit: disabled  
   
     client#  
    

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