The test test_kdcproxy_handles_small_packets_from_ad requires that the traffic between Windows AD DC and IPA server is split into very small packets. Currently this is achieved by configuring Windows Server using following command:
test_kdcproxy_handles_small_packets_from_ad
netsh interface ipv4 set subinterface [iface_name] mtu=70
While this works on Windows Server 2016, the Windows Server 2019 seems to have stricter check for packet size and does not allow to set mtu size less than 576 bytes:
$ netsh interface ipv4 set subinterface Ethernet mtu=575 The parameter is incorrect.
The only solution I can think of is to split packets on IPA server side using iptables.
Metadata Update from @sorlov: - Issue tagged with: tests
Metadata Update from @mpolovka: - Issue assigned to mpolovka
Upon investigation, I've found out that it's possible to change MTU size in Windows Server 2019 using registry manipulation. Investigating viability of this approach
https://github.com/freeipa/freeipa/pull/6330
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