I have two DC in "Site One" - Dual Stack IPv4/IPv6 Network.
One DC in "Site Two" - IPv4 only Network.
Subnets and Site links are configured and this environment worked fine for the past year.
Now I have added another Site "Site One_DMZ1", added the new IPv4 Subnet & IPv6 Prefix. Also created a site link between "Site One" and "Site One_DMZ1" with high cost and 15 min replication. As described by microsoft knowledge base article.
I created a RODC in this _DMZ1 Network but the promote process always hangs.
I figured out, it only hangs when IPv6 is configured. If I disable IPv6, the promote process runs through without problems.
The RODC now run for a few days without problems. Running "repadmin /replsummary" looks good.
Now I have decided to enable back IPv6 on the RODC and now I get error "(1722) RPC server is unavailable" when running repadmin /replsummary.
When I disable IPv6 again, the message disappears (on next replication interval).
The Firewall config between those local networks (v4 & v6) is fully transparent and not filtered (temporarily at the time).
Does anyone here knows a clue how to fix this? We run IPv6 over couple years without problems, hard to think that our IPv6 environment is causing the problem.
Anyone running ADDS over IPv6 here and can confirm it runs smoothly on server 2016/2019 core.