Communication Link Failure Connecting to Amazon
If you receive an error (such as “Physical connection is not useable [xFFFFFFFF]”), when connecting to Amazon SQL Server via a Linked Server or ODBC connection, you need to disable the TCP Chimney Offload setting on your on-premise SQL Server. To do so:
First disable the below settings on the calling machine (found in Local Network Connection -> Network Adapter Properties).
- IPv4 Checksum Offload
- Large Receive Offload (IPv4)
- Large Send Offload Version 2 (IPv4)
- TCP Checksum Offload (IPv4)
- UDP Checksum Offload (IPv4)
Then disable the following settings from the command prompt:
- netsh int ip set global taskoffload=disabled
- netsh int tcp set global chimney=disabled
- netsh int tcp set global rss=disabled
- netsh int tcp set global netdma=disabled
That’s it! You should now be able to connect to Amazon SQL Server.