ipchains rule question: Destination ip

[Joel Hammer]

It has been so long since I set up my firewall I have forgotten why I did
this, so :

Here are two typical rules from my firewall (ipchains). Note that with one,
the target ip is 0.0.0.0, and with the other the target is 68.36.44.105,
which is the ip of the machine running the firewall. eth1 is the external
NIC facing the cable modem.

target      tosa tosx  ifname source          destination         ports

ACCEPT udp  0xFF 0x00  eth1   198.82.161.227  0.0.0.0      * ->   123
ACCEPT udp  0xFF 0x00  eth1   198.82.162.213  68.36.44.105 * ->   123

I have used 68.36.44.105 in a number of destinations in my ipchain
rules instead of 0.0.0.0, as noted above.  As far as I can see, these
rules are equivalent, since my NIC, which is configured as 68.36.44.105,
will not look at packets not addressed to it, at least under ordinary
circumstances.

I would like to remove targets such as 68.36.44.105 and substitute 0.0.0.0
for all of them. Can someone suggest why this might not be a good idea?
For example, I am wondering what would happen if my NIC were to run in
PROMISCUOUS mode ?

Any insight appreciated,

Joel