RPC server is unavailable

[seyah96]

Hello,

I have this weird issue where I can't change domain controllers from ADUC or any active directory services. I'm not sure where to start troubleshooting this kind of issue. I can reach all other domain controller from the problematic DC but I can't do it from other DC's to the problematic DC. 

Any help would be appreciated.

[#2]

Please run;

Dcdiag /v /c /d /e /s:%computername% >C:\dcdiag.log
repadmin /showrepl >C:\repl.txt
ipconfig /all > C:\dc1.txt
ipconfig /all > C:\dc2.txt
ipconfig /all > C:\dc3.txt

ipconfig /all > C:\dc4.txt

ipconfig /all > C:\dc5.txt

then put `unzipped` text files up on OneDrive and share a link.

[#3]

Hi Dave,

Here's the link to the results.

https://1drv.ms/u/s!AvTOVnZsYb5RhzLV5mPTwbYsZfox?e=ovOuSe

Thanks!

[#4]

- BAMAZAD01 is DHCP assigned which should never happen for a domain controller, should always be static!

- On BAMAZAD01 I'd add the server's own static ip address (10.100.5.4) listed for DNS, then do ***ipconfig /flushdns, ipconfig /registerdns***, restart the ***netlogon*** service

- On BAMTORDC02 I'd add the server's own static ip address (10.10.10.182) listed for DNS, then do ***ipconfig /flushdns, ipconfig /registerdns***, restart the ***netlogon*** service

- bardrdc02.txt file is for BAMDRDC02

- dcdiag was run from BAMTORDC02 which seems to have a lot of problems. I'd check the event logs for related errors. Better run from BAMTORDC01

[#5]

@Dave Patrick 

BAMTORDC01 is the problematic server that we can't connect to from ADUC or any active directory services. 

I'm getting a lot of this on BAMTORDC01 

Starting test: KccEvent
* The KCC Event log test
A warning event occurred. EventID: 0x800004C0
Time Generated: 08/31/2021 16:21:41
Event String:
Internal event: An LDAP client connection was closed because of an error.

I'm not sure if moving the DC away from DC OU caused a lot of this issue or not. I just found this out a few minutes ago. 

[#6]

I'd make the corrections, check the event logs and if problems persist put up a new set of files to look at.

[#7]

@Dave Patrick 

I'm not able to connect to BAMTORDC01. I can connect from BAMTORDC01 to other DC from ADUC though. I also tested dcdiag netlogons and BAMTORDC01 failed. 

I have uploaded full test result I ran from BAMTORDC01 on the same onedrive link. 

Please let me know your thoughts.

Thanks! 

[#8]

- A lot of these possibly because of problematic site to site connectivity.

An LDAP client connection was closed because of an error. 1236 The network connection was aborted by the local system.

- I'd work through this one for the Kerberos errors
https://social.technet.microsoft.com/wiki/contents/articles/2064.kerberos-error-code-0x7-kdc-err-s-p...

- The oldest domain controller is 2012 R2 so when you get the domain healthy I'd get the old FRS replication technology migrated to DFSR
https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/Streamlined-Migration-of-FRS-to-DFSR-SYS...

[#9]

@Dave Patrick 

Thank you. What's surprising to me is that replication is still working with all these errors which is a good so I can work through fixing issues slowly. 

Do you think the LDAP issue is the one causing the RPC error? 

[#10]

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Do you think the LDAP issue is the one causing the RPC error? 

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It may be related to poor connectivity. Connection being dropped.

[#11]

It looks like Internal or External Firewall issue. Inbound and outbond AD Traffic need to allow on VPN or Network Firewall.. Windows Firewall also need to check If any AV preventing the AD traffic.
Portquery will let you know the list of ports blocks.
https://www.microsoft.com/en-in/download/details.aspx?id=24009