How dose a firewall work?

I have built myself a SOHO network with two firewalls. I have a cable modem feeding WAN1 of a HotBrick 800/2

my outer firewall.

From there, I have a CAT-5 cable going from LAN1 of that 800/2 going to WAN1 of a HotBrick LB-2

, my inner firewall. My computers are plugged into the 4 LAN ports of the second firewall, the LB-2. For clarity, there are no computers connected to the

800/2 firewall (the first one in the chain), just the second firewall, the LB-2.

I have configured both firewalls to filter out 130.126.0.0-130.126.255.255. I have even filtered ports 1:65535 (all of them) on the outer (800/2) firewall!

Here is my concern.I have downloaded and installed Analog-X's packet monitor

on a computer to see what is going on and this is what I see.

TTL Protocol Checksum SourceIP SourcePort TargetIP TargetPort

113 6 9B94 130.126.138.240 56193 192.168.0.101 1074

113 6 9C07 130.126.138.240 56193

192.168.0.101 1074

113 6 950C 130.126.138.240 56193

192.168.0.101 1074

113 6 9507 130.126.138.240 56193

192.168.0.101 1074

How is this possible? As I understand it, with the packet monitor running on a local computer, it monitors the IP address of the NIC card on that computer.and it sits behind two firewalls! Why does it see packets coming from an IP address that I am specifically blocking? Am I doing something wrong? How can I fix this?

Thanx

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Posted 5 years ago by Anonymous in Networking Firewalls

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