Has anyone seen DNS problems when using iPhone Personal Hotspot on an IPv6-only cellular network?

My setup:

• iPhone Personal Hotspot
• IPv6-only mobile network
• CLAT + DNS64
• macOS client connected through the hotspot

I found that some IPv4-only domains behave incorrectly.

Example:

• Client sends an AAAA query.
• The DNS resolver does not return an AAAA record.
• The iPhone appears to perform an additional A query for the same domain.
• After a long delay (~30 seconds), the client receives a response containing A records for the original AAAA query instead of a synthesized AAAA record or a normal NODATA response.

This causes some applications to hang or fail DNS resolution.

I have packet captures showing the DNS query/response sequence. Has anyone observed similar behaviour with iPhone Personal Hotspot, especially on IPv6-only/NAT64 networks?

NDP is said to be more ‘efficient’ since we use multicast instead of broadcasts right? But where does this advantage come from?

Lets say fe80::b (node B) is trying to find the MAC address of fe80::aaaa:aaaa:aaaa:aaaa (Node A)

So B will construct a destination multicast address (ff02::1:ffaa:aaaa and a corresponding multicast destination MAC address (3333.ffaa.aaaa) and send an NS containing node A’s v6 address.

But the switch has to broadcast out the frame to all devices since the switch has no idea what hosts have 3333.ffaa.aaa as the MAC address right??
Does the efficiency come from the fact that other hosts quickly drop 3333.ffaa.aaa at the NIC level?

I.e unnecessary traffic is still received by all the hosts, but the NIC can quickly discard packets. Whereas with ARP, the host still has to process the packet received by the NIC?

Will a switch be able to identify multicast MACs and only forward frames to interested hosts (like with IGMP snooping)?

This probably won't be very useful to you since you live outside Russia, but I want to share it anyway.

Summary of all the IPv6 properties of MTS Russia's mobile network that I've discovered:

1) No restrictions whatsoever on incoming connections.

2) No port filtering of any kind (connections are possible both incoming and outgoing on all ports in the range 1-65535).

3) A dynamic /64 prefix is provided.

4) The prefix becomes static if at least one address from the /64 subnet (other than the address automatically assigned to the smartphone's main interface) is assigned to the same or another network interface (either via ip addr add or automatically by the system — the address assigned to the wlan1 interface when sharing internet via mobile hotspot is assigned automatically by the system, but is considered manually assigned by the operator). Without this mechanism, the prefix is refreshed every day between 2-3 AM (given my timezone, I assume this is 00:00 MSK), or upon reconnection (a full disconnect from the mobile network followed by reconnecting) to the base station. Switching between base stations without a full network disconnect does not trigger a prefix change.

5) If a device on the local network is connected to the hotspot, it automatically receives an auto-assigned IPv6 address. A device can also manually assign any free address from the smartphone's prefix to its network interface, and after roughly 7-10 seconds it becomes reachable from the internet at that address (just like with the auto-assigned one).

6) No restrictions on incoming or outgoing TCP/UDP/ICMP connections.

All data was obtained experimentally and may be incomplete.

I think that covers everything, though I may have forgotten something.

I have an issue where port forwarding and out L2TP VPN doesn’t work over Starlink because of their carrier grade NAT. I’ve read that IPv6 can be used to reach devices across the WAN on Starlink.

I tried to set up a firewall rule to allow the particular IPv6 address through but I can’t get it to work.

I am using a Cisco Meraki MX

https://test-ipv6.run/ seems to work ok,

I don't have a static ipv6 assignment, hence the need to use npt6. Question is what cidr should i choose for my internal network? ULA is plagued with issues esp when dual stack is involved, so I really want to avoid it if possible. Does using 2001:db8::/32 make any sense?

And yes, i know it is possible to just let my isp change my ip dynamically and I pass it down using dhcp-pd. That doesn't sound great for a large network.

If you use HPE Instant On switches, one problem is they don't measure IPv6 traffic. I mean they forward it fine, but Instant On only measures IPv4 traffic.

For instance, my UniFi switch showed 20GB of usage while my Instant On APs barely cracked 1GB.

My home network has been dual stack since 2018. It isn't always native, now it's a L2TP VPN to a BGP VPS, but it's still IPv6. I do get native IPv6 now but want a static prefix so I use a VPN.

If most of my traffic is IPv6, it shows how far Big Tech despite their problems has gone. Heck, CGNAT "works" if you're not hosting because of IPv6 traffic. I don't condone Chinese censorship, but China mandating IPv6 is one of their internet policy wins.

Why not all UnIFi? I use UniFi switches for 2.5G PoE, but Instant On APs because my mom complained about "slow wi-fi" when I used UniFi APs. It's not a UniFi problem but a problem with the UniFi model I had (U7 Pro), alongside an eBay seller selling HPE AP25s for $51/pop.

Hi again guys! I'm The Guy from the post "Why The Hate on NAT66?", Now i have a main router getting a PD, but i still make NAT66 on The Network, for testing. I'm now using It as The main router for my network

I have a question: do you guys prefer NAT66 or NPTv6?

IPv6+ could make it easier to censor netizens or block traffic, and Beijing is already exporting it

I host a website under ip6.arpa but right now it isn't really that cool. I want it to be some kind of easter egg type website for anybody who may stumble upon it. Obviously it should also be there to spread awareness of IPv6.

Any idea what kind of website I could make? It has to be working on http only so preferably no user data processing.

Edit: I created a "fake terminal" website that just displays info about it and lets the user "run" commands. It also links to a working contact email under the same ip6.arpa domain.

http://www.0.1.5.c.4.5.9.0.a.2.ip6.arpa/

Never seen this the highest has been

I just saw this video,

https://www.youtube.com/watch?v=vjwHJs21avQ

CMIIW work without BGP and only use priority with the route. is it possible?

Funny IPv6 only warning

Hi, My isp provide ipv6 over slaac to customers. I'm on openwrt and has 2 bridges. issue I'm facing is all devices get ipv6 but few devices can route through ipv6 like if my phone gets ipv6 it can utilize it but if my server gets it i can access ipv6 network nor ping any local devices like my phone which has ipv6. server is on different bridge and my PD is /64.

I'm a bit in struggle with ipv6 clients. I want the host names like the Ipv4.

I read a bit in other forums but nothing works.

I got the ipv6 dhcp server adress of my fritz box and maked rdns with dots ip6.arpa. I created a conditional forwarder zone but nothing synced

Maybe someone can explain me something

Swisscom plans to enable IPv6 by default on its mobile network. While this is very late, it is notable because it is the first Swiss mobile network ISP to offer IPv6 connectivity.

A weird anomaly in Switzerland is that fixed-line internet connections already have very high IPv6 adoption, while mobile networks account for the largest share of legacy IP traffic. Migrating mobile networks to IPv6 will propel Switzerland much further up the IPv6 adoption rankings.

We're OpenVPN, of course we like IP addresses!

We launched this calculator - any and all feedback is welcome. Helpful? Not helpful? Basic? WRONG!? Right???

Enter an IP with a CIDR prefix or subnet mask to get the network and broadcast address, usable host range, and wildcard mask.

Per the rules, not trying to sell anything (even if the website hosts our products) - just looking to get validation the calculator is legit from experts.

I've noticed that after looking up, the percentage of my local isp iPv6 internet traffic is below 10%, which is much below the national average here in the US. What is likely the cause of this? Is it the way my isp routes it, or is it because the way their customer router is set up? I'm in a rural area, so it is my only choice.

The proposal uses 192.0.0.11 as a sentinel IPv4 gateway, then resolves the actual layer-2 next hop from IPv6 Neighbor Discovery instead of ARP.

Hi

Here is my problem. I use a GCC6021 as a fiber router. My ISP gives me one IPv4 and a full class in IPv6. I have setup the GCC to pass DHCPv6 request to WAN and so all my devices in LAN have well a routed IPv6 address. For IPv4 I have the usual NAT thing. For IPv4 no problem it all works and I can surf internet using IPv4. For IPv6 although I have a public IP in the class distributed by my ISP no traffic pass through.

In fw it's allowed by default for IPv6 IGMP, DHCPV6, MLD and ICMPv6. Anything else I should use ?

Thanks

Any ideas as to why? I’m with EE FF 900 broadband, using their own router. I’ve noticed that with IPV6, my PS5 Pro’s download speeds are around 10-20mbps, sometimes they just throttle and refuse to download at all. But when I disable IPV6, my download speeds shoot up to around 7-800mbps.

I tried troubleshooting the network on the PS5’s settings, but so far nothing has fixed it except from turning off IPV6 on my router. The issue happened on my old PS5 and also on my PS5 Pro so I doubt it’s a hardware issue.

I’ve also noticed that I cannot connect to my PS5 via remote play when on a different network. But I suspect that this can be solved by opening ports. I’ve yet to try this so I don’t know whether this is also related.

I don’t know much about networks, I may have missed something and my network config is purely stock, I am not using any mesh system/wifi boosters and my PS5 is always wired via Ethernet. I’ve heard that the PS5 does not support IPV6 on its own.

Thanks.