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Tomato wierdness with Modem fullbridge

Discussion in 'Tomato Firmware' started by AciDCooL, Jun 27, 2010.

  1. AciDCooL

    AciDCooL Networkin' Nut Member

    First of all hello to everyone im new to the forum.. didn't even know tomato had a forum haha.

    I've been having a little problem with my tomato router(WRT54GL) in combination with my adsl modem (Thomson ST546 v7).
    When I bought the Thomson I wanted a modem thats just modem and no router functions whatsoever. This was apperently the only solution for my current provider cause they handle PPPoA Authentication.
    So I had to setup the Thomson using the Disk that came with it to Fullbridge mode. Piece of cake.
    Then came the WRT54GL, I allready had the amazing tomato installed. Think it was 1.25 at that time.
    Now with fullbridged modem, tomato recieves the external ipadress, dns, etc. But it didn't make a route. After a bit of searching on the DDWRT forums (yes I migrated from that crappy bloatware) I found this script for in my firewall script section:

    GW=$(nvram get wan_gateway) 
    route add -host $GW dev $(nvram get wan_iface) 
    route add default gw $GW
    This worked, with this script I had my precious internet back.. Now for the wierd part.. Every so now and then when I check my [Status] --> [Devices List] page... it is full of external ip adresses from other people.. not to endanger any people I can't make a screenshot.. But that's just rly rly wierd.. looks like tomato thinks the external network from the provider is a lan-network or something..

    Here is my routing list:

    Code:	*	0	vlan1 (WAN)	*	0	br0 (LAN)	*	0	lo	*	0	vlan1 (WAN)
    default	0	vlan1 (WAN)
    Maybe someone can shed some light on this, I would rly appreciate it.
    Thanks in advance,
  2. mstombs

    mstombs Network Guru Member

    You cannot full-bridge pppoa, you will be using the SpeedTouch in its half-bridge mode "Assign the WAN IP to a lan device" function.

    What netmask does the Speedtouch modem give the tomato router? I suspect it attempts dhcp spoofing with or similar, which would make the router think any IP address with first part same as the router local - with MAC address of modem. This is potentially bad as there is a finite size of the Linux arp-table. Entries drop out of the arp table after about 5 mins of no activity. The Tomato "devices list" is a merge of the "arp table" with the dhcpd lan client list.

    With stock tomato you need those route commands to fix a bug in the stock Linksys/ derived firmwares when the WAN gateway is not in the network defined by the WAN IP address and WAN netmask. I've had to use them with half-bridge since HyperWRT Thibor days, if you search these forums I'm sure you will find the post where Thibor himself told me where to put them!

    You no longer need those firewall commands with teddy_bear's latest Tomato versions, or latest beta dd-wrt. Problem is also avoided in stock Asus RT-N16 code where it appears also to be fixed in Broadcom SDK.
  3. AciDCooL

    AciDCooL Networkin' Nut Member

    Thanks allot m8 Ill go and install teddy_bear's latest mod tonight.. Funny to see that there are mod's of mod's :)

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