except for nor using it at all, of course.
So I want to make my homelab IPv6 ready, because I have too much free time, i guess. There are two decisions that I’m currently unsure about:
- ULA or not. Do you have local only addresses or do your clients communicate using the global IPv6 address? Does not using ULAs work without a static IP from the ISP?
- DHCPv6 or is SLAAC enough?
For each question both options seem to be possible and I’m interested in your experience
Cheers
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My provider doesn’t provide IPv6, but I rented a server in a data center, bought a subnet, and tunneled it home via WireGuard. So the scheme is roughly: VPS (fd00:1::/64) <-> (fd00:1::/64) Home router (realv6/64) <-> Home network
Router configuration:
/etc/sysctl.d/10-ipv6-privacy.conf
net.ipv6.conf.all.use_tempaddr = 0 net.ipv6.conf.default.use_tempaddr = 0 net.ipv6.conf.all.forwarding = 1 net.ipv6.conf.default.forwarding = 1/etc/radvd.conf
interface br0 { AdvSendAdvert on; MinRtrAdvInterval 3; MaxRtrAdvInterval 30; AdvManagedFlag on; # M=1 → Address via DHCPv6 AdvOtherConfigFlag on; # O=1 → Additional options via DHCPv6 # SLAAC is still possible for Android prefix realv6::/64 { AdvOnLink on; AdvAutonomous on; # Allow SLAAC }; RDNSS realv6::1 { AdvRDNSSLifetime 1800; }; DNSSL home.lan { AdvDNSSLLifetime 1800; }; };/etc/kea/kea-dhcp6.conf
{ "Dhcp6": { "interfaces-config": { "interfaces": [ "br0" ] }, "lease-database": { "type": "memfile", "persist": true, "lfc-interval": 86400, "name": "/var/lib/kea/dhcp6.leases" }, "renew-timer": 21600, "rebind-timer": 43200, "preferred-lifetime": 43200, "valid-lifetime": 86400, "subnet6": [ { "id": 1, "subnet": "realv6::/64", "interface": "br0", "pools": [ { "pool": "realv6::1000 - realv6::ffff" } ], "option-data": [ { "name": "dns-servers", "data": "realv6::1" }, { "name": "domain-search", "data": "home.lan" } ] } ], "loggers": [ { "name": "kea-dhcp6", "output-options": [ { "output": "stdout" } ], "severity": "WARN" } ] } }And of course, iptables is necessary. Something like: /etc/iptables/ip6tables.rules
# Generated by ip6tables-save v1.6.0 on Thu Sep 8 13:29:11 2016 *nat :PREROUTING ACCEPT [0:0] :INPUT ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] COMMIT *filter :INPUT DROP [0:0] :FORWARD DROP [0:0] :OUTPUT ACCEPT [0:0] #BASE INPUT -A INPUT -i eno1 -j DROP -A OUTPUT -o eno1 -j DROP -A INPUT -i lo -j ACCEPT -A INPUT -i br0 -j ACCEPT -A INPUT -p ipv6-icmp -j ACCEPT -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -i eno1 -j DROP -A FORWARD -i br0 -j ACCEPT -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -p ipv6-icmp -j ACCEPT COMMITIdk. what assignment we use, but our ISP gave us (company) a prefix and we offer our services (for our team) IPv6 first. IPv4 is only used within the company network where a DNS server resolves the domains if needed.
It works great for us. If my private ISP would allow it, I would do the same.
So for you selfhosted services you use ipv4 only?
Don’t use ULA, those are non internet routable addresses so they will never use v6 for internet things. Use the range assigned from your ISP.
SLAAC. Because Android has one ass of a dev who refuses to include DHCPv6You can use both at the same time and it is useful to have ULA if your ISP changes your assigned prefix.
This is what I do. I haven’t seen a reason to change it as of yet.
I use both ULA and global addresses. Servers set a token to make the last 64bits predictable, which simplifies dyndns. For some critical internal communication, I hard code the ULA address in my hosts file, for everything else, I rely on DNS (with global addresses). No DHCPv6.
I usually just disable IPv4 on my VMs, unless there is a specific need for IPv4. Most container networks are single stack as well. I have a squid proxy that services can use to access IPv4 http/https destinations if really necessary (combined with some additional filter rules); ideally I would like to have 464xlat/a nat64 gateway, but I never bothered to set that up yet. I will likely do that when I buy a new router (end of year?). I expect all my devices to support CLAT by then, so that will be the end of IPv4 on my network.
Disabled. IPv6 is slow af whenever I have it on. As soon as I disable it, my bandwidth goes full speed.
I’m not sure what they were thinking with that technology but it’s dead in the water and we need to find a better protocol. It’s also terribly difficult to memorize. The numbering scheme is worse than the Xbox naming scheme.
Haha this is bait right?
I can’t get IPv6 in any worthwhile form from my ISP. IMHO IPv6 isn’t any more useful than IPv4 if you only have ULA. And NAT is not as well supported since it wasn’t intended to even be really necessary for example. So even if you are starting from scratch or just using it internally, there are some disadvantages to implementing it over just sticking with IPv6. But if your ISP actually provides IPv6 it might be worth it as long as your devices all support it. But otherwise you’re going to need to set up IPv4 in addition, anyway, so you’re just going to create problems for no good reason, IMHO.
Dual stack setups are not an issue unless your router doesn’t support it or your ISP sucks.
But why bother if you get ULAs. It doesn’t enhance anything and adds complexity if you use NAT or other routing as you need to add rules for both IPv4 and IPv6. Most ISPs, in the US anyway, don’t offer true IPv6 only what was supposed to be transitional technology decades ago like 6rd. I hate to say anything good about Comcast, but it’s the single thing I miss from that they actually do. But having such limited upstream speeds on cable just isn’t reasonable for much of anything these days, but definitely not when self-hosting. 1-10Mbps up on Cable or most DSL just doesn’t cut it.
If you’re starting from scratch implementing IPv6 on your LAN might be worthwhile if you dont mind the limitations of or don’t require the transitional technologies on your LAN like NAT64 and the hit to performance from the translations/tunneling when accessing the internet doesn’t bother you (it sure annoyed the hell out of me every time I accessed a website, among other things).
But dual stack, seems like it’s not worthwhile. Just choose one or the other. Few software applications or modern hardware are going to have an issue with IPv6. But if you’re using both ULAs and IPv4 private addresses, it seems like a lot of extra hassle to write duplicate routing rules for everything.
Like I said: unless your ISP sucks. I don’t see the issue with dual stack and I don’t know why you’re bringing other transition mechanisms into this. Obviously they kinda suck. Dual stack really doesn’t have much of a downside or a performance hit unless your clients or DNS are doing something stupid. In which case you can still choose to configure a client to use one over the other. Many ISPs, especially outside the US, don’t have enough IPv4 address space and have to use CGNAT, in which case you’re much better off with a dual stack setup and a DNS config that prefers AAAA records, imho. IPv4 only leaves you with NAT, which sucks and IPv6 only isn’t feasible currently.
I live in spain so the main ISP is well provided with IPv4 blocks and have zero incentive to deploy IPv6 outside of mobile networks. So the IPv6 deployment here is like 3% and I don’t have access to it 🫠
Just static IP, since I have a static subnet delegated by my provider, on a shitty cable modem.
Blocked by my ISP. So I have it all blocked.
Same here, my ISP is IPv4 only so I have it disabled on my router.
The only systems with ip6v in my network are Wi-Fi devices and my public-facing reverse proxy. I use a prefix delegated by my ISP.
All of my non-public servers have ipv4 only.
IPv6 is disabled at the firewall. I’m just not in a hurry to redo my network.
Personal opinion, IPv6 has been on the table so long it’s no longer something I think about. 20 years ago I thought it was going to be amazing.
I use ULA for my WireGuard tunnels, otherwise it’s all public IPv6 (mostly lightly firewalled).
I’m fine with SLAAC, even for servers. I just manually update my DNS with the server addresses when I set them up.
I use global addresses for everything. ULA is the equivalent of the private networks like 10.0.0.0/8 on IPv4. It doesn’t need a static IP. ULA will work without any internet connection. If you run an IPv6 only network, it would be a good idea to set up ULA so you can access your local devices if the internet goes down.
I only use SLAAC on my network because DHCPv6 is not well supported. My router does use DHCPv6 to get a prefix from the ISP though.
set up ULA so you can access your local devices if the internet goes down
your router should retain its address even if the external connection goes down.
DHCPv6 is not well supported
Androids get SLAAC, everybody else can have a nice, readable, stable, firewall-openable suffix.
- Probably wouldn’t hurt to set them up, especially if you don’t have a static prefix. The good thing is that interfaces can have multiple IPv6 addresses, so they can use both the public address and the ULA.
- SLAAC should always be enough. Make sure you don’t block the ICMP6 messages it needs though (I’ve been bitten by that once, firewalld behaves weirdly around this).
In the home/lab, I use public addresses with mostly SLAAC, but the host server has a static IP. I get A public /56 prefix via DHCPv6-PD from my ISP. There is a bit of a pain point if the prefix changes but it hasn’t happened since I moved here.
My ”production” setup is a bit more controversial. Since Hetzner charges extra for extra IPv6 subnets I simply created small /80 subnets for the VMs. While this does mean that SLAAC doesn’t work I can simply generate and assign static IPv6 IPs, same way as I do with IPv4. All generated from an ansible playbook that creates the VMs.
I have some ULA ranges as well, but it’s a bit of a special case as I only use it as internal IP ranges in a Kubernetes cluster. This is completely separated from the external network, with the cluster doing NAT to the node IPs anyway (even for IPv6), and all internal traffic being on an overlay network.
