How To Fix 00664 - Unknown host

SAP Error Message - Details

• Message type: E = Error

• Message class: 00 -

• Message number: 664

• Message text: Unknown host

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

Unfortunately, there isn't any extra information in this error notice.

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Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message 00664 - Unknown host ?

  The SAP error message "00664 Unknown host" typically indicates that the SAP system is unable to resolve the hostname of the server it is trying to connect to. This can occur in various scenarios, such as when trying to connect to a database, application server, or any other network resource.
  Causes:
  
  Incorrect Hostname: The hostname specified in the SAP configuration is incorrect or misspelled.
  DNS Issues: The Domain Name System (DNS) is unable to resolve the hostname to an IP address.
  Network Configuration: There may be network issues preventing the SAP system from reaching the host.
  Hosts File: The entry for the hostname may be missing or incorrect in the local hosts file.
  Firewall or Security Settings: Firewalls or security settings may be blocking access to the host.
  
  Solutions:
  
  Check Hostname: Verify that the hostname is correct in the SAP configuration. This includes checking the instance profile and any connection settings.
  DNS Configuration: Ensure that the DNS server is correctly configured and that the hostname can be resolved. You can test this by using the ping command in the command line:
  ping <hostname>
  
  Update Hosts File: If DNS resolution is not working, you can add an entry for the hostname in the local hosts file (located at /etc/hosts on Unix/Linux or C:\Windows\System32\drivers\etc\hosts on Windows).
  <IP Address> <hostname>
  
  Network Connectivity: Check the network connectivity to ensure that the SAP system can reach the host. This may involve checking network cables, switches, and routers.
  Firewall Settings: Review firewall settings to ensure that they are not blocking access to the host. You may need to allow specific ports or IP addresses.
  SAP Configuration: If the error occurs during a specific transaction or operation, review the relevant SAP configuration settings to ensure they are correct.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any specific guidance or patches related to this error. SAP Notes can provide insights into known issues and their resolutions.
  Logs: Review the SAP system logs (transaction SM21) and developer traces (transaction ST22) for additional context around the error.
  Network Tools: Use network diagnostic tools like nslookup or traceroute to further investigate DNS resolution and network paths.
  
  If the issue persists after trying the above solutions, it may be beneficial to consult with your network administrator or SAP support for further assistance.