I have debian linux on my laptop and connect to the outside world using a
linksys adsl2mue modem and wrt54gs router.
I'm having some problem with connections: due mainly to gross ignorance,
and any help anyone can give would be much appreciated.

The modem IP is 192.168.1.1 and the router is 192.168.2.1

Everything works when the laptop is
running windows xp, but I don't usually want to do that.

Running linux I can ping succesfully but many other programs, ssh, scp,
mozilla, netscape, will not work
unless I find a specific ip number (using ping) and then
use that instead of a domain name. I've tried editing
resolv.conf, with dns servers supplied by my ISP
but so far to no effect.

ifconfig returns the following:
%%%%%%%%%%%%%%%%%%%%%%%%%%%
eth0 Link encap:Ethernet HWaddr 00:11:43:CC:7F:78
inet6 addr: fe80::211:43ff:fecc:7f78/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Interrupt:11

eth1 Link encap:UNSPEC HWaddr
00-11-43-80-00-CC-7F-78-00-00-00-00-00-00-00-00
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:12 errors:0 dropped:0 overruns:0 frame:0
TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:840 (840.0 b) TX bytes:840 (840.0 b)

sit0 Link encap:IPv6-in-IPv4
inet6 addr: ::127.0.0.1/96 Scope:Unknown
inet6 addr: ::192.168.2.3/96 Scope:Compat
UP RUNNING NOARP MTU:1480 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

wlan0 Link encap:Ethernet HWaddr 00:0E:35:A5:1A:2C
inet addr:192.168.2.3 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::20e:35ff:fea5:1a2c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:69 errors:0 dropped:0 overruns:0 frame:0
TX packets:30 errors:0 dropped:0 overruns:0 carrier:1
collisions:0 txqueuelen:1000
RX bytes:3669 (3.5 KiB) TX bytes:2550 (2.4 KiB)
Interrupt:5 Base address:0x5000 Memory:e0210000-e0210fff

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
resolv.conf is:
search
nameserver 192.168.1.1
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
route -n returns

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0
wlan0
0.0.0.0 192.168.2.1 0.0.0.0 UG 0 0 0
wlan0

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Under windows xp ipconfig /all gives
%%%%%%%%%%%%%%%%%%%%%%%
Windows IP Configuration
Host Name . . . . . . . . . . . . : SNITCH
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Broadcast
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Wireless Network Connection:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) PRO/Wireless 2200BG
Network Connection
Physical Address. . . . . . . . . : 00-0E-35-A5-1A-2C
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.2.3
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.2.1
DHCP Server . . . . . . . . . . . : 192.168.2.1
DNS Servers . . . . . . . . . . . : 192.168.1.1
Lease Obtained. . . . . . . . . . : 28 March 2006 12:44:07
Lease Expires . . . . . . . . . . : 29 March 2006 12:44:07
Ethernet adapter Local Area Connection:

Media State . . . . . . . . . . . : Media disconnected

Description . . . . . . . . . . . : Broadcom 570x Gigabit
Integrated
Controller

Physical Address. . . . . . . . . : 00-11-43-CC-7F-78

It looks like your ISP is behind it's own NAT router.
You will not be able to run any kind of server.

Also, they are running a DNS server at:
DNS Servers . . . . . . . . . . . : 192.168.1.1
This happens to be on the same subnet that you are using so queries don't go through the gateway device. You may need to change your local network to something like 192.168.3.

I would recommend a using a different ISP actually. Giving you a private IP address will likely cause other problems.

-----

Sorry, I misread your info. Your network is at 192.168.2 and theirs is at 192.168.1. However, I still think that they are pulling a fast one on you by giving you a private IP address.

My ISP does provide DNS servers but they are
not 192.168.x.x numbers, in fact they start 202.
but they are not always the same.

The DNS sever is the adsl2mue modem which
is 192.168.1.1 and this works fine with windows.

How to get it to work under linux is what I'm trying
to ascertain.

You have the same IP address as eth0 and wlan0. BAD JUJU!!!

Is your modem connected to the router, or your computer? Internal modem? Ethernet? or USB? It seems that getting an address like that is not good.

If connected to computer, connect it to your router on the WAN port (The one by itself)

The reason that things are kludgy and you have a double NAT is that the Linksys ADSL2MUE that Linksys sell as a "modem" is actually a router. It can't do port forwarding or anything due to the highly restrictive web interface, and it only has 1 ethernet port but none-the-less it is a NAT router.

This is why it looks like your ISP is dishing out LAN IPs. Actually this is the "modem" doing stealth NAT

So your current setup is:
...ADSL2MUE..........WRT54G........
--router-----------router------------PCs
...........192.168.1.x.........192.168.2.x

I put some other firmware on my ADSL2MUE which enabled the usual router web admin things like port forwarding and did away with the 2nd router. You might want to try this at your own risk. This firmware is not what Linksys recommends (although it is made by Linksys. I think it's on their ftp somewhere and it worked for me)

You can download it/view a screenshot here
http*//blog.maniacmartin.com/2006/12/07/turning-a-modem-into-a-router/

This made the internet faster to me as I wasnt behind 2 NATs.
(I used a bog standard access point for wireless - maybe your WRT54G can be set to do that????)

Re: DNS. I have never got the ADSL2MUE to get the DNS server IPs from my ISP (Demon) on any firmware (although my Netgear and Speedtouch have no problem). It jsut refused to do it for me. Nor is there a way I can see to enter it manually.

I entered my ISPs DNS servers manually in XP and Linux (make sure you remove 192.168.1.1 as it seems to make things not work.)

Windows:
Start > Control Panel > Network Connections
Right click the one you use > Choose "Properties"
Choose "TCP/IP" > Properties
Set your DNS Servers here

Ubuntu Edgy: (should be similar for other distros
System > Administration > Networking
DNS Tab
Remove 192.168.1.1
Add your ISPs DNS servers
Hit Save icon

If you find a way of getting DNS to set via DHCP please let me know.

I hope my post explains more about this router, even if it doesnt help you in any way

martin
martin /at/ maniacmartin.com