unicast vxlan - unable to tcp connect to ipv6 ip's on endpoint host

[Marco van Tol]

Op 19 apr. 2019, om 14:53 heeft Andrey V. Elsukov <bu7cher at yandex.ru> het volgende geschreven:
> 
> On 19.04.2019 13:46, Marco van Tol wrote:
>> There is one exception to this: Host B can ping Host A on any of its
>> IPv6 addresses, but it cannot make any tcp connection to any of the
>> IPv6 addresses on Host A.  Is this expected?
> 
> Hi,
> 
> this looks like the problem with checksum offloading. When such
> offloading is enabled on the interface, such protocols like TCP and UDP
> defer checksum calculation to interface hardware. ICMPv6 does checksum
> calculation in software, thus it usually does not affected by such
> problem. Sometimes NIC hardware or driver have bugs and offloading does
> not work correctly. You can try to disable checksum offloading on your
> interfaces and then try. Also you can use tcpdump to try determine what
> the problem you have with TCP.

Ha! Thank you very much, this fixed it.

In my case the physical interface used on Host A for transmitting/receiving the vxlan packets was an if_bce interface.

After I did the following on host A, Host B could make an IPv6 tcp connection on for example port 443 of host A.
  ifconfig bce0 -rxcsum

Many thanks!

-- 
Marco van Tol