[nzlug] Networking 101 question

[Patrick Connolly]

Strange as it might seem, I've used Linux for 7 or 8 years and never
had occasion to know anything much about networks.

Now, I'm trying to connect via cross-over cable a laptop running Mepis
6.5 to a desktop running Fedora Core 6, the latter being connected to
an ADSL D-link modem DSL-302.  I never managed to get DHCP working on
that setup, but the modem does work with static address (and a fixed
IP address).


On the desktop, ifconfig gives this:

$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:11:2F:9F:56:97
          inet addr:10.1.1.3  Bcast:10.1.1.255  Mask:255.255.255.0
          inet6 addr: fe80::211:2fff:fe9f:5697/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:59721 errors:0 dropped:0 overruns:0 frame:0
          TX packets:49480 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:51974631 (49.5 MiB)  TX bytes:5765641 (5.4 MiB)
          Interrupt:21 Base address:0x4000

eth1      Link encap:Ethernet  HWaddr 00:10:4B:6F:2F:F4
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::210:4bff:fe6f:2ff4/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:227153 errors:0 dropped:0 overruns:0 frame:0
          TX packets:500011 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:16510852 (15.7 MiB)  TX bytes:706125391 (673.4 MiB)
          Interrupt:19 Base address:0x2c00

 (plus output for lo which I've ignored, so far at least)


and on the laptop, 


$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:90:F5:4B:B2:B5
          inet addr:192.168.0.2  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:591617 errors:0 dropped:0 overruns:0 frame:0
          TX packets:260078 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:839086153 (800.2 MiB)  TX bytes:18808609 (17.9 MiB)
          Interrupt:16 Base address:0xac00

(plus output for eth1 and lo which I think I can ignore)

That doesn't quite show all the settings.  The laptop's gateway
address is 192.168.0.1 (cf eth1 above).

There's probably many better ways of doing it, and I'd certainly like
to improve on this one.  While it's possible to access the internet
from the laptop (the main object of the exercise), and ssh from the
laptop to the desktop works (nearly well enough).  However, I can't
ping 192.168.0.2 from 192.168.0.1 and I'd like to rectify that.  If I
use DHCP on the laptop's network, it allocates 192.168.0.31 but trying
to ssh to that one from 192.168.0.1 also results in no response.  I
don't get any indication in the firestarter events which might
indicate what the holdup might be.

I got most of my information from
http://www.fs-security.com/docs/connection-sharing.php where it was
suggested that there be no default gateway for the eth1 on the desktop
(something else not shown above). It was there that I got the idea of
using firestarter for a firewall.

Suggestions as to what could be done to improve the setup are welcome.

Best

--
   ___     Patrick Connolly      
 {~._.~}   
 _( Y )_          Good judgment comes from experience 
(:_~*~_:)         Experience comes from bad judgment    
 (_)-(_)