Solved IPv6 and internal corporate routing

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Hello ITPro TV! I've been routing with IPv4 for a while now and am trying to wrap my mind around IPv6 infrastructure when it comes to a site to site private link. Whether it me point to point private link or an IPSEC tunnel. In the CCENT class we covered the following prifix address in the IPv6 space.

2000::/3 - E000::/3 - Global unicast (Public registered and routable IPs.)
FC00::/7 - FD00::/7 - Private unicast addresses.. (Like 10.0.0.0/8 with IPv4 only much much larger.)
FF00::/8 - Multicast (discovery, lldp, dhcp)
FE80::/10 - Link local

So as I am thinking through this, if I need to route between two private networks, my workstations are going to end up having three different addresses? Link local for local network connectivity, a public IP for internet access (that might change depending on circuit failover - not using BGP), and a private IP that never changes for internal routing.

@Adam-Tyler said in IPv6 and internal corporate routing:

Hello ITPro TV! I've been routing with IPv4 for a while now and am trying to wrap my mind around IPv6 infrastructure when it comes to a site to site private link. Whether it me point to point private link or an IPSEC tunnel. In the CCENT class we covered the following prifix address in the IPv6 space.

2000::/3 - E000::/3 - Global unicast (Public registered and routable IPs.)
FC00::/7 - FD00::/7 - Private unicast addresses.. (Like 10.0.0.0/8 with IPv4 only much much larger.)
FF00::/8 - Multicast (discovery, lldp, dhcp)
FE80::/10 - Link local

So as I am thinking through this, if I need to route between two private networks, my workstations are going to end up having three different addresses? Link local for local network connectivity, a public IP for internet access (that might change depending on circuit failover - not using BGP), and a private IP that never changes for internal routing.

That sounds like you've got it right. This will be a difficult concept for some of us to grasp since we tend to think of single devices with single IPs .

I'll be honest, I was hoping you were going to tell me that I was nuts. Ya, this will be incredibly difficult to grasp having 3 addresses for all clients on a given network.. Definitely breaks the standard practice we've all been used to for years and years. Brave new world.

So take this a step further in my analogy of this 3 address per host model for internet and internal routing requirements... I heard Don say that DHCP for IPv6 wasn't really a requirement now.. He may have been referring to EUI-64. I realize that Link Local addresses get created automatically and all clients on an ethernet broadcast domain (Sam VLAN) can talk immediately using the IPv6 protocol if it is simply enabled with zero config. I have also seen internet routable IPs get assigned to clients as soon as the internet router has IPv6 service and is "advertising" itself as a route to the IPv6 internet. In addition to this, if you wanted to distribute an internal IPv6 network to your clients for corporate routing, would you then deploy an IPv6 DHCP server with the scope of addresses you'd like to distribute or is there another way of doing this?

Or is everything I just said sadly misinformed? Lol.

-Adam

Ps.... My understanding of the EUI-64 feature/standard is that the device/interface MAC address can be used to complete the last 64 host bits of the 128 bit IPv6 address. With the addition of FF:FE in the middle of the MAC. However I am not sure where the network prefix would be specified..? perhaps from a router...

@Adam-Tyler said in IPv6 and internal corporate routing:

I'll be honest, I was hoping you were going to tell me that I was nuts. Ya, this will be incredibly difficult to grasp having 3 addresses for all clients on a given network.. Definitely breaks the standard practice we've all been used to for years and years. Brave new world.

So take this a step further in my analogy of this 3 address per host model for internet and internal routing requirements... I heard Don say that DHCP for IPv6 wasn't really a requirement now.. He may have been referring to EUI-64. I realize that Link Local addresses get created automatically and all clients on an ethernet broadcast domain (Sam VLAN) can talk immediately using the IPv6 protocol if it is simply enabled with zero config. I have also seen internet routable IPs get assigned to clients as soon as the internet router has IPv6 service and is "advertising" itself as a route to the IPv6 internet. In addition to this, if you wanted to distribute an internal IPv6 network to your clients for corporate routing, would you then deploy an IPv6 DHCP server with the scope of addresses you'd like to distribute or is there another way of doing this?

You can but you don't necessarily need to do it since devices can use the EUI-64 to create it's own IPv6 address for use on different types of networks.

Or is everything I just said sadly misinformed? Lol.

If you're using IPv6 DHCP you're needing to control the address space which is ok too. Then you must follow whatever limitation or guidelines from the ISP.

-Adam

Ps.... My understanding of the EUI-64 feature/standard is that the device/interface MAC address can be used to complete the last 64 host bits of the 128 bit IPv6 address. With the addition of FF:FE in the middle of the MAC. However I am not sure where the network prefix would be specified..? perhaps from a router...

You can statically configure the Network Prefix and use the EUI-64 command to configure the host bit portion of the addresses. The Router Advertisement also can provide the Network ID bit too.

Thanks Ronnie, just one follow up. When you say:

"You can statically configure the Network Prefix and use the EUI-64 command to configure the host bit portion of the addresses. The Router Advertisement also can provide the Network ID bit too."

Other than using the router's advertisement to statically assign the network portion of the IPv6 address for your hosts, how else would you do it? I imagine DHCPv6 is one option. Is there another?

-Adam

@Adam-Tyler said in IPv6 and internal corporate routing:

Thanks Ronnie, just one follow up. When you say:

"You can statically configure the Network Prefix and use the EUI-64 command to configure the host bit portion of the addresses. The Router Advertisement also can provide the Network ID bit too."

Other than using the router's advertisement to statically assign the network portion of the IPv6 address for your hosts, how else would you do it? I imagine DHCPv6 is one option. Is there another?

-Adam

I'm not sure if there is for publicly routable IPv6 address.