IPv6 SLAAC Concepts and Configuration

General
1

Dear All,

I am playing with a SG-300 at home to know more about Networking, and I am trying to have an automatic IPv6 address on my laptop, but for some reason did not work well… I have the FE80 link local still.

Let me show you waht I have in the switch:

 interface vlan 100
 ipv6 enable 
 name 100
 ipv6 address fd2e:339b:a150:100::/64 eui-64
 ipv6 nd dad attempts 1
 ipv6 address autoconfig

In theory looks ok for me, and the switch is configured in mode “router” and works perfectly in Layer 3, I tested doing ping to others VLANs.

The switch uses the “IPv6 address autoconfig” itself to achieve an IPV6 address, and it takes the IPv6 prefix fd2e:339b:a150:100 perfectly! I have checked that part and worked.

Could you help me to understand my issue?

I know that SG-300 is no the best switch to learn Networking, probably I need to change to Catalyst.

Thanks for your help!

With kind regards,

David

2

Hi again,

I have received an official response from Cisco:

“The switch can forward IPv6 traffic, It has ND and ICMPv6 BUT no IPv6 DHCP – therefore it can not give IPv6 addresses to the clients. If you use another DHCP or configure them manually I suppose that all should work fine in the network.”

I am trying to understand why DHCP running is needed to have SLAAC? Actually, we have some ways to get IPv6 addressing on a network:

• DHCPv6 Statefull
• DHCPv6 Stateless
• SLAAC
• Or Fixed IPv6

The reason of not using any DHCP server on our network is the purpose of our SLAAC implementation, giving us the chance to have an IPv6 prefix being advertised in our network and as far as we have on SG-300 documentation, this device should be able to do it. Is there any other reason why SLAAC doesn’t work on the SG-300 model?

I have checked the SG-300 data sheet and shows the RFC 4862 – IPv6 stateless address auto-configuration.

Link

Thanks for your help!

3

And finally the latest response from Cisco:

“In order to use stateless address auto config (SLAAC), you need an external device that does the SLAAC auto config, because our SG300 can not do that. This auto config, can pass through our device, and the Switch itself can be auto configured via that extra device. We refer to this extra device as DHCPv6.”

So, definitely, I cannot use the SLAAC function on this switch,

Thanks anyway.