NAME

       mirred - mirror/redirect action

SYNOPSIS

       tc ... action mirred DIRECTION ACTION [ index INDEX ] dev DEVICENAME

       DIRECTION := { ingress | egress }

       ACTION := { mirror | redirect }

DESCRIPTION

       The  mirred  action allows packet mirroring (copying) or redirecting (stealing) the packet
       it receives. Mirroring is what is sometimes referred to as Switch Port Analyzer (SPAN) and
       is commonly used to analyze and/or debug flows.

OPTIONS

       ingress
       egress Specify  the  direction  in  which  the  packet  shall  appear  on  the destination
              interface.

       mirror
       redirect
              Define whether the packet should be copied (mirror)  or  moved  (redirect)  to  the
              destination interface.

       index INDEX
              Assign  a  unique  ID  to  this  action  instead  of  letting the kernel choose one
              automatically.  INDEX is a 32bit unsigned integer greater than zero.

       dev DEVICENAME
              Specify the network interface to redirect or mirror to.

EXAMPLES

       Limit ingress bandwidth on eth0 to 1mbit/s, redirect exceeding traffic to lo for debugging
       purposes:

              # tc qdisc add dev eth0 handle ffff: ingress
              # tc filter add dev eth0 parent ffff: u32 \
                   match u32 0 0 \
                   action police rate 1mbit burst 100k conform-exceed pipe \
                   action mirred egress redirect dev lo

       Mirror  all  incoming  ICMP packets on eth0 to a dummy interface for examination with e.g.
       tcpdump:

              # ip link add dummy0 type dummy
              # ip link set dummy0 up
              # tc qdisc add dev eth0 handle ffff: ingress
              # tc filter add dev eth0 parent ffff: protocol ip \
                   u32 match ip protocol 1 0xff \
                   action mirred egress mirror dev dummy0

       Using an ifb interface, it is possible to send ingress traffic through an instance of sfq:

              # modprobe ifb
              # ip link set ifb0 up
              # tc qdisc add dev ifb0 root sfq
              # tc qdisc add dev eth0 handle ffff: ingress
              # tc filter add dev eth0 parent ffff: u32 \
                   match u32 0 0 \
                   action mirred egress redirect dev ifb0

SEE ALSO

       tc(8), tc-u32(8)