Re: Fedora 2 - Can't Get on LAN

From: P Gentry (rdgentry1_at_cablelynx.com)
Date: 09/24/04


Date: 24 Sep 2004 08:40:28 -0700


"Luke" <nomail@nospam.com> wrote in message news:<waH4d.143221$3l3.126954@attbi_s03>...
> I'm hoping someone can help me. I just installed Fedora Core 2 on a system
> that was running Red Hat 9. The problem is that I can't get on my LAN. The
> NIC is a Intel Ethernet Pro 100. Here's what I've tried:
>
> 1. cable and NIC adapter are ok (ran fine under Red Hat 9)
> 2. lspci -v shows "Ethernet controller: Intel Corp. 82557/8/9 [Ethernet Pro
> 100]
> Subsystem: Intel Corp. 82559 Fast Ethernet LAN on
> Motherboard"
> 3. I tried both a DHCP setup and a static IP. I used the Network device
> control app under System Tools. I have the gateway and netmask setup
> correctly

If dhcp is available (from ISP?) then you are likely in a subneted
environment and will have a GW IP address for default routes -- see
below.

> 4. ifconfig shows that everything is setup on eth0, buth there is no data
> moving RX bytes = 0 and TX bytes = 0

Probably not needed, but it's always handy to provide ifconfig output.
 Command/data output is _always_ preferred to descriptions of the
output.

> 5. Ran ethereal on another system on the same hub as the Fedora box. It
> showed that ARP packets from the Fedora box were being sent and received

Did you run ethereal on the "problem" host? "arp -v"? "netstat -rc"?

> 6. I can ping the loopback adapter and when assigned a static IP I can ping
> the Fedora box from the Fedora box

Good ...

> 7 Here's the output from route:
> Destination Gateway Genmask Flags Metric Ref Use
> Iface
> 10.1.249.0 * 255.255.255.0 U 0 0
> 0 eth0
> 169.254.0.0 * 255.255.0.0 U 0 0
> 0 eth0
> 127.0.0.1 * 255.0.0.0 U 0 0
> 0 lo
> default * 0.0.0.0 UG 0
> 0 0 eth0
>
> The only conclusion I've left with is that the Fedora box Network stack is
> somehow disconnected from Ethernet adapter. Any help would be greatly
> appreciated. Thanks.

Note the entry for your default route -- there is no gw IP, which
pretty much makes this entry useless and problematic.

Presumably this host sits on the 10.1.249.0 subnet and should be using
a gw on that subnet to route packets beyond the local subnet
(typically 10.1.249.1 or sometimes 10.1.249.254).

If this is strictly a local, private lan made of a single segment,
hosts connected via a hub/switch, then you don't really need a gw as
arp will find the proper mac addresses for the other hosts (since it
appears you've not turned off arp).

If your lan is segmented (ie., employs a router between segments) then
you probably want a default gw (and its IP).

If you wish to restrict this host to "local" traffic, then you don't
need a default route.

If you have a router facing the internet you will have to provide a gw
IP to move traffic for this host.

If you don't need a default route, get rid of the entry. If you need
a default route, provide a gw IP so that the packets (actually the
ethernet frames) are properly addressed.

hth,
prg
email above disabled



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