I just noticed my Linux box responds to broadcast pings. I don't like the idea of being part of a smurf attack, or being discovered by pinging my network's broadcast address. How do I configure the adapter eth0 not to respond to traffic sent to the broadcast address? My IP is dynamic, and my subnet changes frequently, so I can't really firewall off that address. Here is the info from ifconfig and ping -b. Addresses have been changed, for obvious reasons:-
eth0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
inet addr:192.168.123.154 Bcast:192.168.123.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2553 errors:0 dropped:0 overruns:0 frame:0
TX packets:2742 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:1604139 (1.5 Mb) TX bytes:377355 (368.5 Kb)
Interrupt:11 Base address:0x7000
WARNING: pinging broadcast address
PING 192.168.123.255 (192.168.123.255) 56(84) bytes of data.
64 bytes from 192.168.123.154: icmp_seq=1 ttl=64 time=0.049 ms
64 bytes from 192.168.123.254: icmp_seq=1 ttl=64 time=1.04 ms (DUP!)
64 bytes from 192.168.123.154: icmp_seq=2 ttl=64 time=0.061 ms
64 bytes from 192.168.123.254: icmp_seq=2 ttl=64 time=1.04 ms (DUP!)
64 bytes from 192.168.123.154: icmp_seq=3 ttl=64 time=0.069 ms
64 bytes from 192.168.123.254: icmp_seq=3 ttl=64 time=1.24 ms (DUP!)
64 bytes from 192.168.123.154: icmp_seq=4 ttl=64 time=0.047 ms
64 bytes from 192.168.123.254: icmp_seq=4 ttl=64 time=1.02 ms (DUP!)
--- 192.168.123.255 ping statistics ---
4 packets transmitted, 4 received, +4 duplicates, 0% packet loss, time 3032ms
rtt min/avg/max/mdev = 0.047/0.572/1.241/0.520 ms
Any information will be greatly appreciated.
