With 2.2.18 I noticed something that looked interesting:
# /sbin/ip a l dev eth4
7: eth4: <BROADCAST,MULTICAST,PROMISC> mtu 1500 qdisc pfifo_fast qlen 100
link/ether 00:80:c8:c9:b8:14 brd ff:ff:ff:ff:ff:ff
inet x.y.7.252/24 brd x.y.7.255 scope global eth4
Note that the interface is not UP. Whether it's promisc or not does not
However, the address is still pingable from outside, through eth0!
Also noticed the same behaviour in 2.4.10.
Is this the intended behaviour, probably?
One could argue that if interface isn't UP, it shouldn't be able to send
or receive packets at all. I wonder what changing this would break..
Pekka Savola "Tell me of difficulties surmounted,
Netcore Oy not those you stumble over and fall"
Systems. Networks. Security. -- Robert Jordan: A Crown of Swords