Ipv6 on Aaron's Worthless Words

OSPF and Loopback Interfaces

Sun, 31 Jul 2011 00:00:00 +0000

I was studying via Google+ Hangout the other day with CJ and Rob, and one of the topics that came up was that OSPFv2 advertises all loopbacks as 32-bit no matter what the configured mask is. I rarely use loopbacks outside of a lab and had no idea it did that, so I set up a quick lab to see for myself. Sure enough! That’s exactly what I saw.

Of course, being the inquisitive network guys that we are, we went on to discuss methods for making OSPF advertise the configured network instead of the single IP. The guys mentioned two methods - to redistribute the connected interfaces and to manually set the OSPF network type on the loopback. We were using IPv4 during the session, but I went back and added some IPv6 addresses and processes to compare.

Some Exercises with IPv6 ACLs

Fri, 15 Apr 2011 00:00:00 +0000

ACLs in IPv6 aren’t that different from what you’re used to dealing with in the IPv4 world. You create a list of denies and permits for use with some other structure like filtering, PBR, and all sorts of other stuff. Let’s take a look at building an ACL and filtering traffic with it.

For those playing at home, here’s the setup I used to generate the configs and get the output. Execute some click action for the whole thing.

Configuring an IPv6 Tunnel with Hurricane Electric

Thu, 31 Mar 2011 00:00:00 +0000

My ISP at home is great. I have infinite bandwidth because they have no idea how to do any rate limiting. Heck, they’re not even skilled enough to know that I have several public IP addresses from their DHCP server. That means, though, that they’re not ready for IPv6. They’ve ignored my emails and support tickets asking about their deployment strategy, so I gave up and looked at turning up a tunnel with a broker. I chose Hurricane Electric for no particular reason; they were just the first ones I found. The setup was super-easy and works flawlessly.

Routing IPv6 with BGP - The Basics

Thu, 10 Feb 2011 00:00:00 +0000

Are you sensing a theme lately? Since we covered the basics of the main IGPs (I’m an enterprise guy, so no IS-IS comments, please.), I thought I’d try to describe the basics of advertising IPv6 routes over BGP. Yet again, we’re not going to do any route manipulation or change any of the 948284928 BGP attributes. We’re just trying to get routes exchanged.

Configuration

There’s no new version of BGP for IPv6 here. It’s the standard BGP version 4 that we’ve all been using for years, but we’re going to take advantage of the multiprotocol support (MPBGP, RFC 2858 RFC 4760). We’ll get to the differences in a second, but the first thing to do is to set up the BGP process as normal.

OSPFv3 - The Basics

Tue, 01 Feb 2011 00:00:00 +0000

A few hours ago, the last of the IPv4 addresses were allocated by IANA. Now’s the time to learn more about IPv6! Yesterday, I posted about EIGRP for IPv6, so I think I’ll continue the trend by introducing OSPFv3, which is the IPv6 implementation of OSPF. As always, I’m using Cisco routers here. Just as yesterday, this is just a guide to the absolutely basics; if you want to do some funky OSPF magic, you won’t find it here - perhaps in time, though.

EIGRP for IPv6 - The Basics

Mon, 31 Jan 2011 00:00:00 +0000

I’m not going to go all out like Jeremy over at Packetlife.net has, but I’m going to start to discuss a few IPv6 topics. In time (like in September when APNIC runs out of IPv4 addresses), I’m sure I’ll ramp up the IPv6 talk, but let’s start easy and get EIGRP for IPv6 up and running.

Configuration

There are quite a few differences between EIGRP for IPv6 (yes, that’s an official name) and the IPv4 version. First of all, all IPv6 routing is disabled by default on a Cisco router, so, if you’re doing any routing in IPv6, you’ll want to enable it or risk smashing your head into the desk trying to figure out what’s going on.

ROUTE Notes - Implementing IPv6 in an IPv4 Network

Sun, 04 Jul 2010 00:00:00 +0000

Study Questions

Your boss says that ever host in the network needs to be converted over to IPv6 by the end of the day. Which of multipoint tunnels, point-to-point tunnels, or native IPv6 would be the most appropriate to use to help with that conversion?

Native IPv6

The engineering department wants to permanently use IPv6 on their test boxes in two offices. Which of multipoint tunnels, point-to-point tunnels, or native IPv6 would be the most appropriate to use?

Point-to-point tunnels

ROUTE Notes - Routing IPv6

Wed, 30 Jun 2010 00:00:00 +0000

Study Questions

Why would anyone develop a version of RIP that supports IPv6?

I have no idea. Boredom, maybe. Whatever the case, it works just like RIPv2, which is pretty scary.

In EIGRP for IPv4, there are several requirements for two routers to neighbor up. Which of those is not true for EIGRP for IPv6?

The two routers don’t need to be in the same subnet. The concept of the link local address takes care of that need since neighbors always share a common medium like an Ethernet segment or a serial link.

ROUTE Notes - Intro to IPv6

Tue, 29 Jun 2010 00:00:00 +0000

Study Notes

Exactly how big is an IPv6 address?

It’s 128 bits long.

This shouldn’t be on the test, but how many unique addresses is that?

That’s 2^128 or a “3” with 38 zeros after it. That’s also 2^95 addresses for each person on earth.

Surely we’re not writing in binary, are we?

No way. IPv6 uses 32 hex characters. Each character is 4 bits, so we wind up with 128 bits of data.