We have multiple scopes on windows 2012 R2 servers. I had a scope that was having issues with database cleanup (it would say that it was out of available addresses even though there were still 150 addresses available). In troubleshooting I deleted the scope and recreated it. When I tried to configure the failover it failed on the «creation of failover configuration on host server» then it says «the DHCP failover relationship state is not normal. Configure failover failed. Error: 20120». I have been unable to find anything useful on the error 20120. All the rest of my scopes are not having problems with failover.
DHCPWindows Server 2012
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Question
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hello all,
thanks for the time. i am configuring a 2node dhcp hot standby failover. the problem is that i can get a couple of scopes to be configured for failover but then after a bit it loses connections. and then picks up communication. and then fails. this
is constant in the event logs. i have removed the partnerships and tried a few times… but same results. i can telnet from dc01 to dc02 on port 647. should i add a firewall excpetion for it? below are the logs. any help, suggestion,
thought is appreciated.Primary DHCP Server
Log Name: DhcpAdminEvents
Source: Microsoft-Windows-DHCP-Server
Event ID: 20267
Task Category: DHCP Failover
Level: Error
Keywords:
User: NETWORK SERVICE
Description:
Failover protocol message CONNECTACK from server 192.168.1.2 for failover relationship dc01.contoso.com-192.168.1.2 was rejected because message digest failed to compare.Log Name: DhcpAdminEvents
Source: Microsoft-Windows-DHCP-Server
Event ID: 20254
Task Category: DHCP Failover
Level: Information
Keywords:
User: NETWORK SERVICEDescription:
Server has established contact with failover partner server 192.168.1.2 for relationship dc01.contoso.com-192.168.1.2Partner Server Logs:
Log Name: DhcpAdminEvents
Source: Microsoft-Windows-DHCP-Server
Event ID: 20259
Task Category: DHCP Failover
Level: Information
Keywords:
User: NETWORK SERVICEDescription:
The failover state of server: dc01.contoso.com for failover relationship: dc01.contoso.com-192.168.1.2 changed to : COMMUNICATION_INT.Log Name: DhcpAdminEvents
Source: Microsoft-Windows-DHCP-Server
Event ID: 20255
Task Category: DHCP Failover
Level: Error
Keywords:
User: NETWORK SERVICEDescription:
Server has lost contact with failover partner server 192.168.1.1 for relationship dc01.contoso.com-192.168.1.2 .Event ID: 20254
Task Category: DHCP Failover
Level: Information
Keywords:
User: NETWORK SERVICE
Description:
Server has established contact with failover partner server 192.168.1.1 for relationship dc01.contoso.com-192.168.1.2 .
Answers
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the resolution was setting the MTU to 1500.
netsh interface ipv4 set subinterface «Local Area Connection» mtu=1500 store=persistent
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Marked as answer by
Monday, February 29, 2016 1:09 AM
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Marked as answer by
We’re gonna solve the DHCP server authorization issue in this post. Error code looks like below:
“The authorization of DHCP Server failed with Error Code: 20070. The DHCP service couldn’t contact Active Directory.”
This is possibly due to user permissions on AD. Ensure you input Domain Administrator (DA) Credentials in the DHCP Commit dialog box, instead of proceeding with logged in account. There are chances that though you logged into DC using some user credentials, it doesn’t necessarily mean you are DA/EA. It could just be an account Admin locally, but not on Domain/forest. Check the DA user in ADUC and ensure you input those credentials to solve this.
Other things you should try if the credentials are DA is, ensure AD services are up and running. Check launching ADUC, Try Restarting DHCP Server services, Try re-installing DHCP from server manager. If you still encounter any issues, please message here, so we can further look into it to get it resolved.
Cheers!
Chaladi
Hi,
This is not a VMware issue but a configuration problem in your virtual Windows 2012 server.
I’m not a Windows administrator, but I think that your initial preferred DNS server should at least point to your own server instead of to google’s DNS.
You might even have to start over, can’t remember exactly as it’s been a while since I configured one of those, but you have to choose the correct steps for active directory in the wizard while setting up your DHCP server.
I think you’ll have more luck posting this specific issue in one of microsoft’s forums.
—
Wil
| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
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Windows Server 2012 позволяет довольно просто организовать отказоустойчивую конфигурацию из двух DHCP серверов. Выбираем в контекстном меню протокола или конкретной области «Configure Failover…», указываем тип конфигурации (балансировка нагрузки или режим горячей замены) и настраиваем соответствующие параметры (период синхронизации базы, процент обслуживаемых клиентов и т.д.). После этого все настройки первого сервера (области, параметры) автоматически переезжают на второй сервер.
Но, как всегда, есть нюансы.
В моём случае это вылилось в появление ошибки
Error: 20010. The specified option does not exist.
Причина оказалась в том, что для некоторых областей были созданы кастомные параметры (для телефонии). А как выяснилось, параметры, созданные вручную, сервер не может воссоздать автоматически на партнёре. Прописать на областях может, а создать — нет.
Решение — зайти в «Set Predefined Options…» на втором сервере и воссоздать вручную все кастомные параметры, прописанные на первом сервере. Если создавали их не вы, то отличить кастомные параметры от встроенных поможет кнопка «Delete», которая становится активной только в случае выбора параметра, созданного вручную (см второй скриншот). В моём случае, помимо параметров, пришлось прописать ещё и дополнительный Vendor Class. После чего всё успешно отреплицировалось и заработало.
