Comment by sandeepkd
17 hours ago
This is an interesting take, however from what I seen its other way around. Most security conscious operators would only allow IPv4 instead of IPv6. Your ACL rules and tools are still better at handling/managing IPv4 compared to IPv6
> Most security conscious operators would only allow IPv4 instead of IPv6.
I strongly disagree. That's obsolete knowledge, thrown around by people who want to be considered security conscious but haven't actually updated their knowledge in many years. A statement with similar implications might be "security conscious operators require their users to rotate their passwords monthly", which is what a lot of people use to think a decade ago, and now what it really communicates is that you're talking to a dinosaur.
But IPv6 is complex and inherently globally accessible. Yes, NAT IS not supposed to be a firewall but it works like one nonetheless in many cases.
IPv6 will never replace IPv4 because it is a different protocol rather than merely a new version. The name is a lie.
> IPv6 is... inherently globally accessible.
No, it's not. If you really want a NAT there is no reason you can't use a NAT with ipv6. In fact, it can work even better because instead of using a random port for the translation, you can use a random ip address for each connection.
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What do you mean globally accessible? All the devices on my network have global IPv6 addresses for the last 5 years - since my ISP enabled IPv6 but none of them are accessible unless I configure it.
Very weird take, and not supported by facts or evidence, but OK.
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Most IPv4 "security" is a side-effect of NAT. NAT was not intended as a security feature, but it does provide a level of security in the common consumer implementation (PAT, single external IP, unroutable internal network.)
Otherwise, what are the practical differences?
There's more that's been written about configuring/protecting IPv4 networks and if you learn about network security from a mentor or from coworkers at a job, rather than reading books/the internet/LLMs, you're more likely to learn about IPv4 security.
But if you've ever had to deal with endpoint security, if you're just doing static rule based blocking/throttling, /32 or /24 blocking is often your best option. Thanks to CGNAT this often means having a pretty large impact since an ISP's residential customer might end up getting randomly assigned a "bad" address and the cooldown for these rules is often months long or more.
In IPv6 land, you can just block a /128 or even a /64 and rarely hit anyone else in the crossfire.
Blocking /128 is unlikely to block anyone for very long around here. Both the major ISPs give out /56 blocks with prefix delegation. In almost 4 years, mine hasn't changed.