Can't get ipv6 address from router set up as a dhcpv6 server, pkt

[mandolordian]

Hello, 

I can't get an ipv6 address from a router set up as a dhcpv6 server. I've got both a stateful and stateless server setup for the router, and I don't know what I'm doing wrong. I'm trying to get an address for the PC to the far left. I get an ipv6 address on the pc to the right.

Attached is the pkt

[Harold Ritter]

Hi @mandolordian ,

On R1, you need to apply the IPv6 configuration under the sub interface rather than under the main interface.

interface GigabitEthernet0/0/1

description Link to LAN 1

ip address 10.0.0.1 255.255.255.0

duplex auto

speed auto

!

interface GigabitEthernet0/0/1.100

description Client Network

encapsulation dot1Q 100

ip address 192.168.1.1 255.255.255.192

ipv6 address 2001:DB8:ACAD:1::1/64

ipv6 dhcp server IPv6-STATEFUL

!

Regards,

[mandolordian]

Thank you for that, however, I had to apply the command ipv6 address autoconfig to the interface g0/0/1.100 for pc 1 to obtain an ipv6 address. Is that how it's supposed to be done? I expected that without that command it would work just fine. That command isn't in the switching, routing, and wireless essentials course material, in the DHCPv6 sections. Unless I missed it.

[Harold Ritter]

Hi @mandolordian ,

The "ipv6 address autoconfig" is in no way needed your scenario. It is used when a router receives a router advertisement (RA) from an upstream router and the router needs to auto configure itself using the SLAAC procedure, which is not the case here.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6/command/ipv6-cr-book/ipv6-i1.html#wp2212047392

Regards,

[mandolordian]

I see. I'll upload my current pkt file below, because without the command ipv6 address autoconfig I was not getting an IPv6 address on PC 1.

[Harold Ritter]

Hi @mandolordian ,

You need an ipv6 prefix corresponding to the address prefix specified. ipv6 dhcp pool for routing to work properly. Remove the "ipv6 address autoconfig" and configure "ipv6 address 2001:db8:acad:1::1/64" on the subinterface instead. 

Regards,

[mandolordian]

Hello Harold,

I started on a different pkt file, similar project, same topology as the original post. But, I got rid of the sub-interfaces in Router0. I am getting an IPv6 address from Router0 on PC0. Router0 is set up as a Stateful DHCPv6 server for both networks. I can not get an IPv6 address on PC1, however. Can you tell me what I am doing wrong?

I've attached the pkt file, if you need to have a look at it.

These are the commands I used to set up the server, R1 = Router0:

R1(config)# ipv6 dhcp pool ipv6-stateful

R1(config-dhcpv6)# address prefix 2001:db8:acad:1::/64

R1(config-dhcpv6)# dns-server AAAA:BBBB:CCCC:DDDD::FFFF

R1(config-dhcpv6)# domain-name stateful.com

R1(config)# interface g0/0/1

R1(config-if)# ipv6 nd managed-config-flag

R1(config-if)# ipv6 dhcp server ipv6-stateful

R1(config-if)# exit

R1(config)# ipv6 dhcp pool R2-stateful

R1(config-dhcp)# address prefix 2001:db8:acad:3::/64

R1(config-dhcp)# dns-server AAAA:BBBB:CCCC:DDDD::FFFF

R1(config-dhcp)# domain-name stateful.com

R1(config)# interface g0/0/0

R1(config-if)# ipv6 dhcp server R2-stateful

R1(config-if)# ipv6 nd managed-config-flag

[Harold Ritter · Accepted solution]

Hi @mandolordian ,

You can't have Router0 to server as a dhcp server for PC1, as it is not directly connected. You need to move the ipv6 dhcp pool R2-stateful to Router1 and configure the interface towards PC1 as follow:

interface GigabitEthernet0/0/1

ipv6 nd managed-config-flag

ipv6 dhcp server R2-stateful

!

[mandolordian]

thanks so much. that did it

[mandolordian]

In this particular pkt file, I did not configure sub-interfaces on Router 0. Does that play a role in anything? Is that why I can not get IPs? I couldn't get an IPv4 address on PC0 with this one.

[mandolordian]

I am now having another issue. I am having trouble getting an IPv6 address on both PC's now that I have implemented trunking. In this pkt file, I did not configure the sub-interfaces to Router0.

I have attached the pkt file below.

Implement 802.1Q trunking.

S1(config)#interface f0/5
S1(config-if)#switchport mode trunk
S1(config-if)#switchport trunk native vlan 1000

S1(config-if)# switchport port-security violation restrict

S1(config-if)# switchport trunk allowed vlan 100,200,1000

S1(config-if)#vlan 1000

S1(config-vlan)#name Native

S2(config)#interface f0/5
S2(config-if)#switchport mode trunk

S2(config-if)#switchport nonegotiate
S2(config-if)#switchport trunk native vlan 1000

S2(config-if)#vlan 1000

S2(config-vlan)#name Native

S2(config-vlan)#exit

• Configure access ports.

S1(config)#vlan 100

S1(config-vlan)#name Clients

S1(config-vlan)#exit

S1(config)#interface F0/6

S1(config-if)#switchport mode access

S1(config-if-range)#switchport access vlan 100

S1(config-if-range)#no shutdown

S1(config)#vlan 999

S1(config-vlan)#name Parking_Lot

S1(config)# interface range f0/1-4,f0/7-24,g0/1 - 2

S1(config-if-range)# switchport mode access

S1(config-if-range)# switchport access vlan 999

S1(config-if-range)# shutdown

S1(config-if-range)# exit

S2(config)#interface F0/18

S2(config-if)#switchport mode access

S2(config-if)#switchport access vlan 1

S2(config-if)# no shutdown

• Secure and disable unused switchports.

S2(config)# interface range f0/1-4,f0/7-17,f0/19-24,g0/1-2

S2(config-if-range)# switchport mode access

S2(config-if-range)# shutdown

S2(config-if-range)# exit

• Document and implement port security features.

S1(config)# interface range f0/1-4,f0/6-24,g0/1 – 2

S1(config-if)#switchport port-security

S1(config-if)# switchport port-security violation restrict

S1(config-if)#switchport port-security maximum 4

S1(config-if)#switchport port-security mac-address sticky

S2(config)#interface F0/18

S2(config-if)#switchport port-security

S2(config-if)# switchport port-security violation restrict

S2(config-if)#switchport port-security maximum 4

• Implement DHCP snooping security.

S1(config)# ip dhcp snooping

S1(config)# interface f0/5

S1(config-if-range)# ip dhcp snooping trust

S1(config)# interface range F0/1-4,F0/7-24,g0/1-2

S1(config-if-range)# ip dhcp snooping limit rate 10

S1(config-if-range)# exit

S1(config)# ip dhcp snooping vlan 1,100,200,999,1000

S2(config)# ip dhcp snooping

S2(config)# interface f0/5

S2(config-if)# ip dhcp snooping trust

S2(config)# interface F0/18

S2(config-if)# ip dhcp snooping limit rate 10

S2(config-if)# exit

• Implement PortFast and BPDU guard.

S1(config)# interface range F0/1-4, F0/7-24, g0/1-2

S1(config)#spanning-tree portfast

S1(config)#spanning-tree bpduguard enable

S2(config)#spanning-tree portfast default

S2(config)# interface range f0/5,f0/18

S2(config)#spanning-tree portfast

S2(config)#spanning-tree bpduguard enable

[mandolordian]

see reply...

[Georg Pauwen]

Hello,

without subinterfaces, the native Vlan on the trunk needs to be equal to the Vlan the PC host is attached to (Vlan 100 in your case).

Change the native Vlan on the trunk to 100.

Attached the revised file...