linux - why i can not disable multicast request -

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i use following command disable eth0 interface's multicast mode , not works :

sudo ifconfig eth0 -multicast

when this, eth0's configure so:

ifconfig -v eth0   eth0    link encap:ethernet  hwaddr 00:16:3e:e8:43:01             inet addr:10.232.67.1  bcast:10.232.67.255  mask:255.255.255.0           broadcast running  mtu:1500  metric:1           rx packets:46728751 errors:0 dropped:0 overruns:0 frame:0           tx packets:15981372 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            rx bytes:8005709841 (7.4 gib)  tx bytes:3372203819 (3.1 gib)

then, icmp echo_request in host 10.232.67.2:

ping 224.0.0.1

and tcpdump package on host 10.232.67.1:

tcpdump -i eth0 host 224.0.0.1 -n  tcpdump: verbose output suppressed, use -v or -vv full protocol decode listening on eth0, link-type en10mb (ethernet), capture size 96 bytes 21:11:03.182813 ip 10.232.67.2 > 224.0.0.1: icmp echo request, id 3639, seq 324, length 64 21:11:04.184667 ip 10.232.67.2 > 224.0.0.1: icmp echo request, id 3639, seq 325, length 64 21:11:05.186781 ip 10.232.67.2 > 224.0.0.1: icmp echo request, id 3639, seq 326, length 64

so, how disable multicast mode ?

by way , when disable broadcast:

sudo ifconfig eth0 -broadcast

error message :

warning: interface eth0 still in broadcast mode.

so, why can't stop broad cast mode ?

to disable multicast on interface (you had right):

ifconfig eth0 -multicast

tcpdump without -p flag puts interface in promiscuous mode, captures traffic on wire. if you're on hub, can see traffic sent to/from else. when interface isn't in promiscuous mode, ignores traffic not sent it. if try tcpdump , ping without promiscuous mode, , multicast disabled, shouldn't see traffic:

tcpdump -p -i eth0 host 224.0.0.1 -n

you don't want disable broadcast mode. designates broadcast address subnet.


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