Security question

[Sasa Stupar <sasa@xxxxxxxxxxxxxxxxxxxx>]

What is the potential security problem if you have network as follows:

SOLUTION 1

INET-CABLE MODEM-----------------|
ROUTER-eth0-public IP address----|
ROUTER-eth1-private IP address---|------->SWITCH
ROUTER-eth2-private IP address---|
Internal server for mail,web-----|
all LAN users with private IP----|


SOLUTION 2

INET-CABLE MODEM-->eth0-ROUTER|--eth1|
			       --eth2|-->SWITCH
		 server and LAN users|

I am thinking of the solution 1 because cable modem is a little bit to 
far away from the router and I don't want to use to much of the cables. 
I have setup router with MAC address filtering and also put firewall on 
all internal computers.

What is possible security problem comparing the 2 solutions above?

Regards,
Sasa