Creates a port mirror inside a GRE tunnel. Useful when one needs to create a port mirror and doesn't have access to the necessary network equipment, or when mirroring to a HA VM which may move host ocassionally.
gretunnel sniffs TCP/UDP packets from an interface and sends them out the same or different interface to the specified destination encapsulated in a GRE header.
Usage: gretunnel.exe dst-ip src-ip listen-index send-index
dst-ip destination IP address
src-ip source IP address
listen-index adapter index to listen on
send-index adapter index to send on
Removes GRE headers from packets.
Usage: grestrip.exe iIndex
iIndex adapter index to strip GRE headers from
- Install the WinpktFilter runtime from https://www.ntkernel.com/windows-packet-filter/ on source and destination machines
- On source machine, run gretunnel
- On destination machine, create firewall exception for GRE (IP protocol 47)
- On destination machine, run grestrip