Building IPv6 Firewalls: IPv6 Security Myths

Jonathan MathewsPublic

Firewall rules

We’ve been trundling along nicely in IPv6, and now it is time to keep my promise to teach some iptables rules for IPv6. In this two-part series, we’ll start by examining some common IPv6 security myths. Every time I teach firewalls I have to start with debunking myths because there are a lot of persistent weird ideas about the so-called built-in IPv6 security. In part 2 next week, you will have a nice pile of example rules to use.

Security yeah, no

You might recall the optimistic claims back in the early IPv6 days of all manner of built-in security that would cure the flaws in IPv4, and we would all live happily ever after. As usual, ’tisn’t exactly so. Let’s take a look at a few of these.

IPsec is built-in to IPv6, rather than added on as in IPv4. This is true, but it’s not particularly significant. IPsec, IP Security, is a set of network protocols for encrypting and authenticating network traffic. IPsec operates at the Network layer. Other encryption protocols that we use every day, such as TLS/SSL and SSH, operate higher up in the Transport Layer, and are application-specific.

IPsec operates similarly to TLS/SSL and SSH with encryption key exchanges, authentication headers, payload encryption, and complete packet encryption in encrypted tunnels. It works pretty much the same in IPv6 and IPv4 networks; patching code isn’t like sewing patches on clothing, with visible lumps and seams. IPv6 is approaching 20 years old, so whether certain features are built-in or bolted-on isn’t relevant anyway.

The promise of IPsec is automatic end-to-end security protecting all traffic over an IP network. However, implementing and managing it is so challenging we’re still relying on our old favorites like OpenVPN, which uses TLS/SSL, and SSH to create encrypted tunnels.

IPsec in IPv6 is mandatory. No. The original specification required that all IPv6 devices support IPsec. This was changed in 2011 RFC 6434 Section 11 from MUST to SHOULD. In any case, having it available is not the same as using it.

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