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Author Topic: IPv6  (Read 3213 times)

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Offline prissi

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IPv6
« on: November 10, 2016, 09:30:08 PM »
Benjad reported problems connecting with the serverlist. Further investigation revealed that he does not have a unique IP4 address any more, only an IPv6 (he is using the comcast network). I am surprise he can see the forum (maybe there is some Proxy-Server in between). How is the IPv6 Status currently? As far as I know the nameservers are IP4 only, so this might be the first problem for anyone using IPv6.

Offline DrSuperGood

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Re: IPv6
« Reply #1 on: November 10, 2016, 10:08:32 PM »
IPv6 was designed with IPv4 support in mind in order to facilitate a smooth transitioning. I think the most common approach is IPv4 over IPv6, where it embeds an IPv4 inside an IPv6 and sends it to some gateway higher up (IPv6 is hierarchical). As far as servers are concerned it should act just like any other IPv4 address connecting since the connection is between the gateway identified by an IPv4 and the server using IPv4 with the IPv6 part being masked by the gateway for compatibility.

An IPv6 address will only be connected to if the DNS reports back with an IPv6 address. This needs DNS servers that support IPv6 which, for logical reasons, should have an IPv6 address.

I think at this time it is pretty critical that all servers be made IPv6 ready, even if their hosts are not currently. As it is most ISPs will be switching to IPv6 in the next 2 or so years. Although IPv4 compatibility will remain, probably for decade odd, it will be done through NAT-like gateways which might have firewalls as well as lower quality of service.

My ISP is already starting to transition its customers to IPv6 addresses only, with an IPv4 gateway higher up for backwards compatibility.

Simutrans itself should already be IPv6 ready, as long as one builds not in IPv4 only mode (why does that even exist?).

Offline prissi

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Re: IPv6
« Reply #2 on: November 10, 2016, 10:22:09 PM »
There were some platforms (like Windows 98) which did not had full IPv6 support then.

The serverlist should be fine with IPv6, but the simutrans nameserver only have IP4 addresses.


Offline Ters

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Re: IPv6
« Reply #3 on: November 11, 2016, 06:53:29 AM »
IPv6 was designed with IPv4 support in mind in order to facilitate a smooth transitioning. I think the most common approach is IPv4 over IPv6, where it embeds an IPv4 inside an IPv6 and sends it to some gateway higher up (IPv6 is hierarchical). As far as servers are concerned it should act just like any other IPv4 address connecting since the connection is between the gateway identified by an IPv4 and the server using IPv4 with the IPv6 part being masked by the gateway for compatibility.

While IPv6 has reserved a range for IPv4 addresses, I have never gotten the impression that it specifies how exactly IPv6-only hosts are to communicate with IPv4-only hosts. From 6 to 4 is easy, getting the answer back is the tricky part. That seems to be covered by multiple other competing standards. Maybe Comcast has chosen a proxy-type solution rather than a NAT-type solution, and however this serverlist-thing is accessed doesn't recognize the proxy-settings (or the proxy doesn't support the protocol)? The vast majority of traffic to IPv4-only hosts are probably HTTP/HTTPS coming from the major browsers.

The serverlist should be fine with IPv6, but the simutrans nameserver only have IP4 addresses.

Which means that the only differences between accessing the forum and the serverlist should be the client, plus possibly the network configuration the server is on (I'm thinking of the stuff that blocked DrSuperGood a while back), the server software itself and the protocol being used. If the serverlist is just an off-the-shelf webserver serving the list over HTTP/HTTPS, then the latter two can most likely be ruled out. If the serverlisting is on the same subnet as the forum, the network part can also be ruled out, but wasn't it the serverlisting that was the problem the last time as well?

There were some platforms (like Windows 98) which did not had full IPv6 support then.

Windows 9x support has been dropped, so there is nothing requiring this configuration option anymore, then?

Offline prissi

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Re: IPv6
« Reply #4 on: November 12, 2016, 10:21:24 AM »
Adding to this, www.simutrans.org just gives the message that simutrans.com does not work. Maybe redirecting to simutrans.com is a better idea?

Offline An_dz

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Re: IPv6
« Reply #5 on: November 12, 2016, 10:03:15 PM »
I've fixed the redirect ;)