Azure VPN Gateway
An Azure service that enables the connection of on-premises networks to Azure through site-to-site virtual private networks.
1,803 questions
Can't establish barracuda vpn to azure key mismatch
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Scotti Luca
0
Reputation points
We can't connect using site to site vpn connection. we use barracuda firewall. It always says the there is a shared key mismatch.
Azure VPN Gateway
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Tech-Hyd-1989 5,816 Reputation points2023-06-28T10:22:41.3433333+00:00 Hello Scotti Luca
If you are experiencing a shared key mismatch error when trying to establish a site-to-site VPN connection between Azure and your Barracuda firewall, here are some steps to troubleshoot the issue:
Verify Shared Key Configuration:
- Ensure that the shared key (pre-shared key) configured on both the Azure VPN Gateway and the Barracuda firewall match exactly.
- Double-check for any typos, extra spaces, or special characters in the shared key configuration. The shared key is case-sensitive.
Consistent Key Encryption Settings:
- Confirm that the encryption algorithms and key settings configured on both the Azure VPN Gateway and the Barracuda firewall match.
- Check the key length, encryption protocols (IKEv1 or IKEv2), and encryption algorithms (AES, 3DES, etc.) configured on both ends.
- Make sure that the Phase 1 and Phase 2 settings for key exchange and encryption are consistent on both sides.
- Firewall Configuration:
- Review the configuration settings on your Barracuda firewall related to the VPN connection.
- Ensure that the firewall allows the necessary protocols (such as UDP ports 500 and 4500) for the VPN connection to pass through.
- Verify that there are no conflicting firewall rules or access control policies that may interfere with the VPN connection.
NAT Traversal (NAT-T) Configuration:
- Check if the Barracuda firewall supports NAT-T and if it is enabled.
- If you are using Network Address Translation (NAT) between the Barracuda firewall and Azure, ensure that NAT-T is properly configured on both ends.
Firmware and Compatibility:
- Verify that your Barracuda firewall is running the latest firmware version available.
- Review the compatibility requirements and recommendations provided by both Azure and Barracuda to ensure that the firewall model and firmware version are supported.
Logging and Debugging:
- Enable logging and debug options on the Barracuda firewall to capture detailed information about the VPN negotiation process.
- Analyze the logs for any error messages, negotiation failures, or specific details that can help identify the cause of the shared key mismatch.
Contact Barracuda Support:
- If the issue persists, consider reaching out to Barracuda Support for assistance. They can provide guidance specific to your Barracuda firewall model and help troubleshoot the shared key mismatch problem.
By following these steps and addressing the possible causes of a shared key mismatch, you should be able to resolve the issue and establish a successful site-to-site VPN connection between Azure and your Barracuda firewall.
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GitaraniSharma-MSFT 50,096 Reputation points Microsoft Employee Moderator2023-06-29T14:45:33.54+00:00 Hello @Scotti Luca ,
Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.
If the error says, "there is a shared key mismatch", then you need to validate the pre-shared key on both sides again. Particularly on Azure side, do not copy & paste the pre-shared key as it may include spaces which could cause this issue. Rather type the key in the connection object.
Barracuda recommends that the shared secret can consist of small and capital characters, numbers, and non alpha-numeric symbols, except the hash sign (#). So, make sure that the shared key is created accordingly.
Kindly let us know if the above helps or you need further assistance on this issue.
Regards,
Gita
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