cross-posted from: https://lemmy.world/post/224140
My home ISP does CGNAT for IPv4, but provides native IPv6. I can use IPv6 just fine to access most of my resources, except for one specific server. I can access the server over IPv4 from my home network, and either over v4 or v6 from other networks I’ve tried. But I can’t access it over IPv6 from my home network.
What could be the problem here? Where do I begin to diagnose it
Can you test that site from someone else’s ISP, and from someone else near you on the same ISP?
From other ISPs it works fine. I haven’t checked from someone else using the same ISP, but that’s a good idea. Thanks!
Check your ip address config on the destination server. Does it have a public ipv6 address assigned? Does your server routing table have a default route for that ipv6 network? Does your firewall only allow ipv4?
Yes, I can reach the IPv6 on the server from other networks. I don’t think it’s a firewall issue.
How far does a traceroute get you? That could help isolate where the issue may be.
I’ve looked at one, but all that I can tell is I stop reaching things somewhere between my ISP and the datacenter the server is in.
I kinda think it may be on the isp then, maybe a v6 routing issue? You could work around with an ipv4 tunnel, then route ipv6 through it. If that’s possible, I’ve never done it haha.
Yeah, ISP-related issue is all I can think of. I can connect to the server over v4 no problem, but the broken v6 connectivity to this particular endpoint is strange and nothing I’ve seen before…
I bet they get less reports on ipv6 issues than with ipv4. I have definitely seen carriers have ipv4 routing issues in enterprise networking.
