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I spent a week without IPv4 to understand IPv6 transition mechanisms

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Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#51
post #48
post #40

Earlier quoted context omitted.

NAT and a Firewall are two different concepts. What's wrong with a firewall that blocks everything by default, yet all your devices have a public IP?

Maybe you don't want to reveal your internal infrastructure to the world? Seems like basic opsec.

There's no chance of anybody guessing your infrastructure just by looking at your subnet. (Minimum is /64, which is HUGE!)

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#52
post #8

I am quite happy that all those shady IoT devices cannot be reached from the internet directly when I am using IPv4 and NAT - what would be the best way forward to keep it that way in a IPv6-only future? The best idea I can come up with (at least right now) is: put all less trustworthy (read: Closed source) devices into a special legacy IPv4 network and only use IPv6 on my workstation and little Raspis?

Although I'm going to get comments saying this is wrong...

What I did was:

- IPv6 DHPC - private address range within: fc00::/7

- IPv6 NAT, same as for IPv4.

- Firewall.

Why:

- digital ocean only allowed ~16 IPv6 addresses.

- I wanted a local IPv6 network exiting through digital ocean.

- I see no reason to give public route-able addresses to each device in my home (allows remote websites to determine who is calling it and set up profiles/target each remote device).

- Sure, privacy extensions which cycle unique addresses, but it still allows profiling based on source address, even if a bit of work is needed for each new addresses.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#53

Earlier quoted context omitted.

That's what a firewall is for, NAT does nothing here.

I know, did you read my whole post?

It just makes little sense.

With IPv6 instead of NAT deciding that port 2000 maps to 192.168.1.3 port 22, you have a firewall that may or not choose to route to xx:yy:zz or not, and to allow an incoming connection over port 22 to that host or not.

If you don't want to accept incoming connections to a given machine or network on IPv6 without NAT that's very easy to have.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#54

Earlier quoted context omitted.

Network segmentation, i.e use of vlans is the traditional way to solve this.

Not sure why you’re being downvoted, this is a very good answer. Maybe because you left out the implied “and then firewall off that vlan”?

Yeah, it seems to be the common consensus to just block everything going in and just make exceptions, where you really want to offer a service to the internet.

Makes total sense, thinking about it. I guess, all those years of just sitting behind a NAT makes one forget all these networking basics if you're not using them regularly.

Moving closed-source IoT devices into a special vlan, with some even more rigid rules (something like: only allow http/https traffic into the internal network) might be an additional level of security.

Thank all of you for your replies!

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#55
post #22

Earlier quoted context omitted.

Increased number of available IP addresses, improved security features, simplified network management, reduced network complexity, and support for new technologies. IPv6 also provides significant performance benefits for mobile networks, IoT devices, and cloud services. The adoption of IPv6 will lead to cost savings, improved network performance, and increased scalability.

[flagged]

Unless you're calling NAT "more secure", yes, I maintain that IPv6 is more secure. It simplifies network security operations and especially makes it easier to understand your network when you start visualizing logs and data with a real threat hunting platform. Try dealing with IPv4+IPv6 vs IPv6-only in one of those dashboards.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#56

Earlier quoted context omitted.

I know, did you read my whole post?

It just makes little sense. With IPv6 instead of NAT deciding that port 2000 maps to 192.168.1.3 port 22, you have a firewall that may or not choose to route to xx:yy:zz or not, and to allow an incoming connection over port 22 to that host or not. If you don't want to accept incoming connections to a given machine or network on IPv6 without NAT that's very easy to have.

Maybe people don't want to disclose the number and purposes of interior machines?

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#57

Everyone always goes with the "You don't need NAT, everything is globally routable!" argument, as if that's something that anybody wants. Everything on my network is going to go through my firewall anyway. I don't want anything on my network to be globally routable. Of course, this is not a good reason to not use IPv6, don't get me wrong. It's a problem that's easy to overcome, I just think it's not a good way to get…

> Everything on my network is going to go through my firewall anyway.

Yes, and that's a very reasonable configuration.

But UDP hole punching (very widely used for VoIP, online gaming etc.) works orders of magnitude better with IPv6 than with IPv4, since there is no address and port translation to worry about.

With IPv4, it's very hit or miss, since it depends on both sides' NATs and also requires additional infrastructure (i.e. STUN discovery servers).

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#58
post #43
post #8

I am quite happy that all those shady IoT devices cannot be reached from the internet directly when I am using IPv4 and NAT - what would be the best way forward to keep it that way in a IPv6-only future? The best idea I can come up with (at least right now) is: put all less trustworthy (read: Closed source) devices into a special legacy IPv4 network and only use IPv6 on my workstation and little Raspis?

Put internet of shit devices on their own VLAN(s). Almost all wifi APs today support multiple SSIDs with separate VLANs. Have your firewall block inbound connections to devices on that VLAN. Every OS firewall has built-in support for this. I spent a lot of time figuring out how to do all this in the most efficient way (in terms of my time and effort) during covid, and I suggest getting any arbitrary box with 2 ethern…

I actually thought about that for a minute when I set up my home network a while ago, but that seems to be a pretty hard (or at least inconvenient) problem.

Often I need to access a device from my local network (think: use my phone to control Wi-Fi LED Strips, Sonos speakers, etc.), which makes it impossible (I guess?) to separate these devices into their own network completely (if they aren't controlled by an online service in general). Or is it possible to allow access from my trusted network INTO the restricted network, but not the other way around?

Total network noob here, in case you haven't figured that out yet. :)

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#59
post #8

I am quite happy that all those shady IoT devices cannot be reached from the internet directly when I am using IPv4 and NAT - what would be the best way forward to keep it that way in a IPv6-only future? The best idea I can come up with (at least right now) is: put all less trustworthy (read: Closed source) devices into a special legacy IPv4 network and only use IPv6 on my workstation and little Raspis?

> what would be the best way forward to keep it that way in a IPv6-only future? Firewalls. You configure what traffic should be allowed from who to who. Default deny incoming traffic, and its the same behavior as when you had a NAT. Something having a routable IP address doesn't mean it needs to receive all traffic addressed to it.

The problem I have had with this setup is allowing inbound traffic to things that need it becomes tricky. Some devices don't support DHCPv6 like Android) and some firewalls don't let you do suffix matching. With a dynamic block via PD, the rules to allow inbound traffic to say an Xbox become quite complicated.

Re: I spent a week without IPv4 to understand IPv6 transition mechanisms

#60
post #38
post #21

I still think IPv6 can be safely ignored. This articles section "here are some reasons you should start using IPv6 within your own network" seems to comfirm this. None of the 6 "reasons" speak to me.

Here's an easy one for you: if you have a gigabit connection, most home routers can barely handle the load of NAT. That's why gamers push for IPv6. It's mentioned in the article but few people realize how inefficient NAT can be at gigabit and more. My ISP router could do max 800 mbps, which isn't so bad, but it degraded when we were multiple people using the link. With IPv6 it's much less of a problem, we can easily…

> if you have a gigabit connection, most home routers can barely handle the load of NAT.

I remember reading about this as well. Wouldn't that also apply to stateful firewalling, though? Or is NAT inherently more computationally difficult (e.g. due to having to recompute IP and/or TCP/UDP checksums) than checking a state table?

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