[Gllug] Half-Bridge Configuration on Conexant ADSL router/modem

[Dylan]

Hi all,

Arising from the ADSL modem discussion, I want to configure the 
'Half-Bridge' mode on my modem.

I currently have the following setup:

modem: WAN IP <fixed>
              LAN IP 10.0.0.2/255.0.0.0
              NAT
I
v
gateway: eth0 - DHCP from modem on 10.0.0.0
              : eth1 - 192.168.250.251/255.255.255.0
              NAT
I
v
switch
I
v
LAN (192.168.250.0)

AIUI, the half bridge mode will give:

modem: WAN IP <fixed>
              LAN IP 10.0.0.2/255.0.0.0
I
v
gateway: eth0 - DHCP from modem = fixed external IP
              : eth1 - 192.168.250.251/255.255.255.0
              NAT
I
v
switch
I
v
LAN (192.168.250.0)

thus removing a layer of NAT and giving me more control over routing and 
address/port forwarding etc. and all incoming packets will hit eth0 on 
the gateway. 

I'm not entirely sure how I need to configure the routing table on the 
gateway in order to get this to work correctly. The current rout table 
in the modem is:

DEST			MASK			GATEWAY		INTERFACE
0.0.0.0			0.0.0.0			195.166.128.11	ppp1
10.0.0.0			255.0.0.0			10.0.0.2			br0
127.0.0.1			255.0.0.0			127.0.0.1			lo0
195.166.128.11	255.255.255.255	<my static IP>	ppp1

I understand the first 3 lines, but what is the last line there for?

So far, so good. Am I right in thinking the following is correct for the 
route table on the gateway:

DEST			MASK			GATEWAY		INTERFACE
0.0.0.0			0.0.0.0			195.166.128.11	eth0
10.0.0.0			255.0.0.0			10.0.0.2			eth0
127.0.0.1			255.0.0.0			127.0.0.1			lo0
195.166.128.11	255.255.255.255	<my static IP>	eth0

Do I need to alter the modem's routing table to account for the gateway?

Cheers
Dylan

-- 
"They that can give up essential liberty to obtain a little 
temporary safety, deserve neither liberty nor safety." 
                                  -Benjamin Franklin

-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug