[solved] Can't call some sites with iPV6

[sumehl]

Hello,

i have the problem that some site like "forum.kde.org". Ping6 works on that, but not call the website. If i disable ipv6 it works. On my colleague, he get ipv6 directly from provider, not over an tunnel, there the website is working. So what can i do that the site works also with ipv6?

Thanks and best regards

[cholzhauer]

It sounds like you may have an mtu issue somewhere

What kind of internet connection do you have?

[sumehl]

Hello,

i have an normal wire connection from A1 here in Austria. Firewall and connection to the ipv6 tunnelbroker is an Fortigate.

[sumehl]

What can i do with the mtu size?

[snarked]

The minimum MTU size for IPv6 is 1,280 bytes.  Try setting your MTU to that value and see if it works then.  If not, then the problem might not be your configuration.  I have also noted that sometimes there is a routing problem over IPv6 which isn't there via IPv4 - especially where the two paths are distinctly different.

[sumehl]

Thanks a lot for your reply. So I'am not an networkspecialist... where i enter the mtusize? In the Fortigate Firewall, or at the tunnelbrokerportal?

[cholzhauer]

You can set it on the advanced settings page for your tunnel.

[sumehl]

Strange, it was on 1280, so i changed to default 1480 and now it is working well :)

Very Thanks for the help!