Signed-off-by: Phil Sutter <p...@nwl.cc> --- man/man8/tc-mirred.8 | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/man/man8/tc-mirred.8 b/man/man8/tc-mirred.8 index 52d98bc416563..bba96e0e5d8c0 100644 --- a/man/man8/tc-mirred.8 +++ b/man/man8/tc-mirred.8 @@ -21,11 +21,9 @@ mirred - mirror/redirect action .SH DESCRIPTION The .B mirred -action allows to redirect or mirror packets to another network interface on the -same system. It is typically used in combination with the -.B ifb -pseudo device to create a shrared instance where QoS happens, but serves well -for debugging or monitoring purposes, too. +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. .SH OPTIONS .TP .B ingress @@ -67,9 +65,23 @@ debugging purposes: .EE .RE -Use an +Mirror all incoming ICMP packets on eth0 to a dummy interface for examination +with e.g. tcpdump: + +.RS +.EX +# 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 +.EE +.RE + +Using an .B ifb -interface to send ingress traffic on eth0 through an instance of +interface, it is possible to send ingress traffic through an instance of .BR sfq : .RS -- 2.7.2
