I did a session at SharkFest’18 Europe in Vienna with the title of “Crash Course: IPv6 and Network Protocols“. Since the presentation slides + audio were recorded you can listen to the talk, too. Here are some notes about the motivation for this session as well as feedback from the attendees.
During the last few weeks I published a couple of blogposts concerning routing protocols such as BGP, OSPFv3, and EIGRP. (Use the “Cisco Router” tag on my blog to list all of them.) They are all part of my current Cisco lab that I am using for my CCNP TSHOOT exam preparation. While I depicted only the details of the routing protocols in those blogposts, I am showing my overall lab with all of its Cisco IOS configs here. Just to have the complete picture. There are a couple of not-yet-blogged configs such as VRRP, GLBP, NTP authentication, embedded event manager (EEM), or route-maps and distribute/prefix lists though.
And again: Here comes a pcapng capture taken for the dynamic routing protocol EIGRP. If you want to dig into EIGRP messages, download the trace file and browse around it with Wireshark. Since I used both Internet Protocols (IPv6 and legacy IP), MD5 authentication, route redistribution, etc., you can find many different messages in it.
Yet another routing protocol I played with in my lab. ;) This time: EIGRP, Enhanced Interior Gateway Routing Protocol, the
proprietary distance-vector routing protocol developed by Cisco, which is now public available (RFC 7868). However, no third-party products in here but only Cisco routers. I am using named EIGRP for both Internet Protocols, IPv6 and legacy IP, along with MD5 authentication and redistribution from OSPF.
Here comes a small lab consisting of three Cisco routers in which I used OSPFv3 for IPv6 with IPsec authentication. I am listing the configuration commands and some show commands. Furthermore, I am publishing a pcapng file so that you can have a look at it with Wireshark by yourself.
For those who are interested in analyzing basic BGP messages: I have a trace file for you. ;) It consists of two session establishments as I cleared the complete BGP session on two involved routers for it. Refer to my previous blogpost for details about the lab, that is: MP-BGP with IPv6 and legacy IP, neighboring via both protocols as well, with and without password. The involved routers were 2x Cisco routers, one Palo Alto Networks firewall, and one Fortinet FortiGate firewall.
While playing around in my lab learning BGP I configured iBGP with Multiprotocol Extensions (exchanging routing information for IPv6 and legacy IP) between two Cisco routers, a Palo Alto Networks firewall, and a Fortinet FortiGate firewall. Following are all configuration steps from their GUI (Palo) as well as their CLIs (Cisco, Fortinet). It’s just a “basic” lab because I did not configure any possible parameter such as local preference or MED but left almost all to its defaults, except neighboring from loopbacks, password authentication and next-hop-self.
If you have ever read some docs or RFCs about IPv6 you should be quite familiar with the 2001:db8::/32 “IPv6 Address Prefix Reserved for Documentation”, RFC 3849. This RFC clearly states how you should handle addresses within this range: “This assignment implies that IPv6 network operators should add this address prefix to the list of non-routeable IPv6 address space, and if packet filters are deployed, then this address prefix should be added to packet filters.”
I was interested whether those addresses are actually used in the Internet. For this purpose I analyzed my firewall logs for 6 months to get an idea. Though it was not that much, I actually got a couple of connections inbound and outbound (!) sourced or destined to those reserved IPv6 addresses.
While there are many approaches on how to structure your IPv6 prefix into /64 subnets (blogposts, books, talks) there are only a few hints what you can do with the other 64 bits of the addresses, namely the IPv6 interface identifier or IID. To my mind you can put some (but not too much) logic into those IIDs to a) have some structure for your addresses that b) helps you identifying those addresses when seeing them in logs or anywhere else. Hence it is easier for you to remember the IPv6 address behind a name (forward DNS) as well as the host when seeing the address (reverse DNS).
This post just shows the approach I am using in my lab. You might find it useful or you might disagree completely. Anyhow, feel free to comment your experiences or solutions for that. :D I am wondering why there isn’t much discussion about these IIDs at all. Maybe for some good reasons I am not seeing yet?
If you’re following my blog you probably know that I am using IPv6 everywhere. Everything in my lab is dual-stacked if not already IPv6-only. Great so far.
A few months ago my lab moved to another ISP which required to change all IP addresses (since I don’t have PI space yet). Oh boy! While it was almost no problem to change the legacy IPv4 addresses (only a few NATs), it was a huge pain in the … to change the complete infrastructure with its global unicast IPv6 addresses. It turned out that changing the interface IPv6 addresses was merely the first step, while many modifications at different services were the actual problem. And this was *only* my lab and not a complex company or the like.
Following you find a list of changes I made for IPv6 and for legacy IP. Just an overview to get an idea of differences and stumbling blocks.
Some time ago I published a pcap that can be used to study basic IPv6 protocol messages such as ICMPv6 for Router Advertisements, Neighbor Solicitations, etc.: “Basic IPv6 Messages: Wireshark Capture“. You can use it to learn the basic IPv6 address assignment and layer 2 address resolution. However, that pcap does not include any upper layer protocols.
This time I captured a few application layer protocols that I used over IPv6 rather than over legacy IP. Common user protocols such as DNS, HTTP/S, IMAP, SMTP (with STARTTLS), as well as some network administration protocols: SSH, SNMP, and Ping. It is not that interesting at all ;) though you can use it to have some examples for Wireshark to prove that those application protocols are almost the same when run above IPv6 compared to IPv4.
Just a few days ago I gave a talk at Troopers 18 in Heidelberg, Germany, about the problems of dynamic (non-persistent) IPv6 prefixes, as well as IPv6 VPNs in general. Following are my slides and the video of the talk:
I am using Nmap every time I installed a new server/appliance/whatever in order to check some unknown open ports from the outside. In most situations I am only doing a very basic run of Nmap without additional options or NSE scripts.
Likewise I am interested in how the Nmap connections appear on the wire. Hence I captured a complete Nmap run (TCP and UDP) and had a look at it with Wireshark. If you’re interested too, feel free to download the following pcap and have a look at it by yourself. At least I took some Wireshark screenshots to give a first glance about the scan.
And one more IPsec VPN post, again between the Palo Alto Networks firewall and a Fortinet FortiGate, again over IPv6 but this time with IKEv2. It was no problem at all to change from IKEv1 to IKEv2 for this already configured VPN connection between the two different firewall vendors. Hence I am only showing the differences within the configuration and some listings from common CLI outputs for both firewalls.
Towards the global IPv6-only strategy ;) VPN tunnels will be used over IPv6, too. I configured a static IPsec site-to-site VPN between a Palo Alto Networks and a Fortinet FortiGate firewall via IPv6 only. I am using it for tunneling both Internet Protocols: IPv6 and legacy IP.
While it was quite easy to bring the tunnel “up”, I had some problems tunneling both Internet Protocols over the single phase 2 session. The reason was some kind of differences within the IPsec tunnel handling between those two firewall vendors. Here are the details along with more than 20 screenshots and some CLI listings.