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.
With PAN-OS version 8.0 Palo Alto Networks introduced another IPv6 feature, namely “NDP Monitoring for Fast Device Location“. It basically adds a few information to the existing neighbor cache such as the User-ID (if present) and a “last reported” timestamp. That is: the admin has a new reporting window within the Palo Alto GUI that shows the reported IPv6 addresses along with its MAC addresses. This is really helpful for two reasons: 1) a single IPv6 node can have multiple IPv6 addresses which makes it much more difficult to track them back to the MAC address and 2) if SLAAC is used you now have a central point where you can look up the MAC-IPv6 bindings (comparable to the DHCP server lease for legacy IPv4).
Haha, do you like acronyms as much as I do? This article is about the feature from Palo Alto Networks’ Next-Generation Firewall for Internet Protocol version 6 Neighbor Discovery Protocol Router Advertisements with Recursive Domain Name System Server and Domain Name System Search List options. ;) I am showing how to use it and how Windows and Linux react on it.
Anstelle von technischen Details heute mal ein Erfahrungsbericht. Vielleicht sollte ich eher sagen: ein Odysseebericht. Für einen meiner Kunden habe ich den Business-Internetanschluss umgezogen. “Einfache Sache”, so dachte ich anfangs, zumal der alte und neue Anschluss beide bei dem gleichen Anbieter liegen: der Telekom. Von einem “Company Connect” der T-Systems (ok, doch nicht exakt Telekom) hin zu einem DeutschlandLAN Connect IP.
Es war fürchterlich:
And finally the throughput comparison of IPv6 and legacy IP on a Juniper ScreenOS firewall. Nobody needs this anymore since they are all gone. ;) But since I did the same speedtests for Palo Alto and FortiGates I was interested in the results here as well.
Following is a list of the most common Cisco device configuration commands that I am using when setting up a router or switch from scratch, such as hostname, username, logging, vty access, ntp, snmp, syslog. For a router I am also listing some basic layer 3 interface commands, while for a switch I am listing STP and VTP examples as well as the interface settings for access and trunk ports.
This is not a detailed best practice list which can be used completely without thinking about it, but a list with the most common configurations from which to pick out the once required for the current scenario. Kind of a template. Of course with IPv6 and legacy IP.
While preparing for my CCNP SWITCH exam I built a laboratory with 4 switches, 3 routers and 2 workstations in order to test almost all layer 2/3 protocols that are related to network management traffic. And because “PCAP or it didn’t happen” I captured 22 of these protocols to further investigate them with Wireshark. Oh oh, I remember the good old times where I merely used unmanaged layer 2 switches. ;)
In this blogpost I am publishing the captured pcap file with all of these 22 protocols. I am further listing 46 CHALLENGES as an exercise for the reader. Feel free to download the pcap and to test your protocol skills with Wireshark! Use the comment section below for posting your answers.
Of course I am running my lab fully dual-stacked, i.e., with IPv6 and legacy IP. On some switches the SDM template must be changed to be IPv6 capable such as sdm prefer dual-ipv4-and-ipv6 default .
After I have done some speedtests on the FortiGate firewall I was interested in doing the same tests on a Palo Alto. That is: What are the throughput differences of IPv4 vs. IPv6, measured with and without security profiles, i.e., with and without threat prevention.
It turned out that the throughput is much higher than the official information from Palo Alto. Furthermore, I was not able to test the threat prevention at all, because non of my traffic (Iperf and mere HTTP) went through the antivirus engines. I have to test this again. However, here are the measured values so far:
The most common transition method for IPv6 (that is: how to enable IPv6 on a network that does not have a native IPv6 connection to the Internet) is a “6in4” tunnel. Other tunneling methods such as Teredo or SixXS are found on different literatures as well. However, another method that is not often explained is to tunnel the IPv6 packets through a normal VPN connection. For example, if the main office has a native IPv6 connection to the Internet as well as VPN connections to its remote offices, it is easy to bring IPv6 subnets to these stations. Here comes an example with two Palo Alto firewalls.
I was interested in the performance of my FortiGate firewall when comparing IPv4 and IPv6 traffic. Therefore I built a small lab consisting a FortiWiFi 90D firewall and two Linux clients running Iperf. I tested the network throughput for both Internet Protocols in both directions within three scenarios: 1) both clients plugged into the same “hardware switch” on the FortiGate, 2) different subnets with an “allow any any” policy without any further security profiles, and finally, 3) activating antivirus, application control, IPS, and SSL inspection.
It’s really great that the FortiGate firewalls have a DHCPv6 server implemented. With this mandatory service, IPv6-only networks can be deployed directly behind a FortiGate because the stateless DHCPv6 server provides the DNS server addresses. (This is unlike Palo Alto or Cisco which have no DHCPv6 server implemented.)
However, the configuration on the FortiGate is really bad because nothing of the IPv6 features can be set via the GUI. (And this is called a Next-Generation Firewall? Not only the features count, but also the usability!) Everything must be done through the CLI which is sometimes hard to remember. Therefore I am publishing this memo of the appropriate CLI configuration commands.
I am lucky to have a full dual-stack ISP connection at home. However, the ISP only offers a dynamic IPv6 prefix with all of its disadvantages (while no single advantage). In this post, I am summarizing the limitations of a dynamic prefix and some of the ideas on how to overcome them. I am always comparing the “IPv6 dynamic prefix” state with the legacy “dynamic IPv4 address” situation. I suppose that some of these problems will hit many small office / home office locations during the next years.
Of course, IPv6 ISP connections with dynamic prefixes should only be purchased at private home sites. It is no problem to have new IPv6 addresses there because all connections are outbound. However, many small remote offices (SOHO) might rely on such cheap ISP connections, too. If they provide some servers in a DMZ or other components such as network cameras, building components with IPv6 connections, etc., they will run into these kind of problems. (The remote office could even tunnel every outbound IPv6 traffic through a VPN to the headquarter. But if it wants to use a local breakout, this won’t be an alternative.)