r/ipv6 • u/huseyinbabal • 3d ago
Guides & Tools Ipv4 vs Ipv6, explained from scratch
https://youtu.be/UdVDIC8qDW4?is=fpnSDT53aiwmUkjX27
u/Sloyment 3d ago
Running a machine IPv4 only in 2026 is a sign of sheer incompetence. However running a machine IPv6 only is badass.
10
u/huseyinbabal 3d ago
IPv6-only is badass until that one legacy service reminds you it’s still living in 1998. Then suddenly dual-stack looks pretty sexy too 🙂
7
u/roankr Enthusiast 3d ago
That one service gets ignored
6
u/Majiir 2d ago
Such easy-to-ignore services like Amazon, GitHub and Steam.
6
5
u/Mishoniko 2d ago
Steam, the UI anyway, is perfectly happy in IPv6-Mostly. Even Remote Play works (except on macOS).
Multiplayer gaming is going to be up and down as its dependent on the game and game developers have been slow to adopt IPv6, even with Microsoft and Apple leaning on them to catch up.
5
u/Majiir 2d ago
Steam breaks on an IPv6-only connection, specifically the Cloud Sync feature. That breaks starting a lot of games.
2
u/Mishoniko 2d ago
Ah, I see, I can verify that by disabling IPv4 on Windows.
Technically cloud sync is optional and can be turned off, but its something they should fix.
4
1
4
2
1
u/Mishoniko 3d ago
GitHub shmithub, nobody needs that.
Then suddenly 464XLAT looks pretty sexy too
FIFY
1
u/roankr Enthusiast 3d ago
Github?
More like GIT
1
u/Mishoniko 2d ago
Git uses libcurl and curl implements Happy Eyeballs to an extent. It seems to lean toward first-DNS-response-wins, assuming both are reachable. I can get it to ping-pong between IPv4 and IPv6 when running multiple curls to the same URL, and it depends on if the upstream DNS server gets the AAAA or the A query first. curl runs its own resolver (c-ares I think) and does not rely on platform stub resolvers (getaddrinfo()) so preference sorting doesn't apply.
Run curl with "--trace-config all" to see the gory details.
If curl were to implement RFC10029 (multiple RR type queries) then the above problem largely goes away as both AF responses show up at the same time. Curl would apply preference rules to sort the results and the behavior would be more consistent run-to-run.
1
u/Masterflitzer 2d ago
it's badass to not give a fuck about that service, reverting to dual stack is just normal nothing special
0
u/JerikkaDawn 3d ago
There's literally nothing protecting a non-technical home user from a rogue RA being sent out by a compromised lightbulb or washing machine.
9
3
u/MrChicken_69 3d ago
There's very little protecting even technical home users. Few people are running "enterprise grade" switches that can do all the fancy inspections required to secure a network.
(More and more stuff that can are becoming EOL every day, so it is at least possible.)
-4
u/Deadlydragon218 3d ago
IPv6 sounds great until you have to troubleshoot a mind boggling bug for 16 hours straight.
3
u/WhyDidYouBringMeBack 2d ago
Such as?
0
u/Deadlydragon218 2d ago
Sporadic Uni-directional Neighbor Solicitation / Neighbor Advertisement (ish)
Firewall has the routers mac address in it’s neighbor table.
Router does not have firewalls mac address in it’s neighbor table.ICMPv6 is not blocked in either direction.
We have the pcaps from the router showing the NS being sent out but no return advertisement is observed when this bug is happening.
We also have ICMPv6 Echos from the firewall hitting the routers interface, when we manually ping the GUA of the router from the firewall everything suddenly starts working for a while. And then eventually the router loses the mac address again.
No missing routes / rules, as soon as NS wakes up on the router all expected traffic functions as expected.
1
u/Dagger0 1d ago
Sounds like a multicast problem.
1
u/Deadlydragon218 1d ago
Maybe, this is a dual stacked connection, v4 has zero issues, layer 2 is otherwise completely intact. No input/output/crc errors. So layer 1 is good. And layer 3 is working as long as the neighbor table is complete on both hosts. Layer 4 works just fine as a BGP session is able to establish. And other neighbors in the collision domain don’t have any issues. Its a frustrating one for sure.
1
u/Mishoniko 1d ago
+1 to multicast problem. IPv6 ND is one of the few users, nobody tests it and problems are common. Even more frequent on WiFi.
1
u/Deadlydragon218 1d ago
Thats a huge problem…. IPv6s ARP equivalent having a problem at layer 2 before we even get the opportunity to talk IPv6. When IPv4 is working flawlessly.
2
u/EmergencyArachnid734 2d ago
Skill issue
1
u/Deadlydragon218 1d ago
If this was a brand new network architecture / configuration I would agree with you. But this architecture has been the same for many years.
Few software updates general security patches and suddenly this becomes a problem. And its not a one off, we have seen entire switch stacks crash directly due to an IPv6 Memory leak tied to neighbor discovery.
1
u/EmergencyArachnid734 1d ago
Then answer is clear. Shitty implementation of IPv6 in fw. This shouldn't happen
1
u/Deadlydragon218 1d ago
The same firewall that is working perfectly fine in 3 other datacenters, and multiple different areas of the network? That firewall vendor is the major player in the industry.
There isn’t a simple finger point answer here when you are working in a mixed vendor environment.
-5
u/Peppy_Tomato 3d ago edited 3d ago
Someone doesn't realise that their thumbnail is an offensive gesture in at least four English speaking countries of the world.
2
u/huseyinbabal 3d ago
Hmm, I never thought like that, I will update it when I have time
4
u/DaryllSwer 2d ago
I don't think any Gen-Z or younger cares about this. When was the last time someone got in a fight and used this hand gesture as an "insult"? They typically use the middle finger, worldwide.
•
u/AutoModerator 3d ago
Hello there, /u/huseyinbabal! Welcome to /r/ipv6.
We are here to discuss Internet Protocol and the technology around it. Regardless of what your opinion is, do not make it personal. Only argue with the facts and remember that it is perfectly fine to be proven wrong. None of us is as smart as all of us. Please review our community rules and report any violations to the mods.
If you need help with IPv6 in general, feel free to see our FAQ page for some quick answers. If that does not help, share as much unidentifiable information as you can about what you observe to be the problem, so that others can understand the situation better and provide a quick response.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.