{"id":1185,"date":"2026-10-01T16:29:11","date_gmt":"2026-10-01T16:29:11","guid":{"rendered":"https:\/\/blog.miguelsarmiento.com\/?p=1185"},"modified":"2026-10-01T16:29:11","modified_gmt":"2026-10-01T16:29:11","slug":"ipv6-delegation-pfsense-cisco-oh-my","status":"publish","type":"post","link":"https:\/\/blog.miguelsarmiento.com\/?p=1185","title":{"rendered":"IPv6 Delegation, PfSense, Cisco, Oh My!"},"content":{"rendered":"\n

Hello there,<\/span><\/p>\n\n\n\n

The topic of this blog may not be that relevant since IPv6 is being around now for many years.<\/span><\/p>\n\n\n\n

However, I still see issues once in a while on forums, with IPv6 delegation and how to configure it on PfSense.<\/span><\/p>\n\n\n\n

Since I can not control how my ISP delegates IPv6 to me, the next best thing is to lab the hell out of it.<\/span><\/p>\n\n\n\n

Keep on reading.<\/span><\/p>\n\n\n\n\n\n\n\n

Motivation<\/strong><\/h2>\n\n\n\n

I have used delegation from my ISP, today I use a consumer router that gives you a \/64, in the past I have used a Fedora box running IPTABLES. <\/span><\/p>\n\n\n\n

You request a prefix via DHCPv6, store what your provider gives you, configure the LAN interface with one those prefixes and voila you are ready to go.<\/span><\/p>\n\n\n\n

I have a blog showing how I did it using Fedora as my Internet router.<\/span><\/p>\n\n\n\n

You would think that PfSense would be that easy, since it is running a secure version of Linux. Well you would be wrong!<\/span><\/p>\n\n\n\n

So, I decided to be my own ISP, use a Cisco router, delegate prefixes to a Cisco router acting as a client and a PfSense firewall.<\/span><\/p>\n\n\n\n

You probably did guess it.<\/span><\/p>\n\n\n\n

On Cisco devices is a piece of cake, on the PfSense well you will see.<\/span><\/p>\n\n\n\n

Setup, IPv6 Delegation and Routing<\/strong><\/h2>\n\n\n\n

The following figure shows the network I am using<\/span>.<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

Figure 1. Delegation Diagram.<\/p>\n\n\n\n

    \n
  1. It has a Cisco 7600 acting as the ISP router. It will delegate IPv6 prefixes.<\/li>\n\n\n\n
  2. A Cisco router (test) that receives a prefix and then gets configured.<\/li>\n\n\n\n
  3. A PfSense router (second client) that also gets a prefix and gets configured.<\/li>\n\n\n\n
  4. A couple of devices to test what addresses Pf Sense gives.<\/li>\n<\/ol>\n\n\n\n

    IPv6 Delegation<\/b><\/i><\/h3>\n\n\n\n

    First we need some background on how delegation works since every time that I see issues on forums, people do not seem to understand how IPv6 works, how routing works and how delegation is used.<\/span><\/p>\n\n\n\n