FCoE or iSCSI can get I/O errors when net.ipv4.ip_forward sysctl is enabled

Issue

• This is a physical machine that is connected to a SAN. Whenever the server is rebooted, I/O errors are displayed in the console and logs.

Sep 25 15:00:30  kernel: [   85.677399] sd X:0:0:15: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677463] sd X:0:0:16: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677516] sd X:0:0:17: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677569] sd X:0:0:18: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677618] sd X:0:0:19: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677642] sd X:0:0:20: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677666] sd X:0:0:21: rejecting I/O to offline device
Sep 25 15:00:30  kernel: [   85.677689] sd X:0:0:22: rejecting I/O to offline device

• Seen while IP forwarding is being enabled, either manually or by some user space daemon:

# sysctl -w net.ipv4.ip_forward=1