Strange problems with eth1

[omcaree]

Hey all,

 

I've been experiencing some strange problems with my network recently, since moving house/isps. I'll try to explain the situation as best I can, but feel free to ask for clarification!

 

I have a computer connected to my DSL router (this router is effectively acting as just a modem), which acts as a router and a fileserver, I'll call this PC1. Connected to PC1 (via ethernet) I have my main PC (PC2) , and a wireless access point. I have dhcpd running on PC1, configured for two subnets: 192.168.2.x (interface connected to PC1) and 192.168.0.x (interface connected to the access point). When I connect my laptop (windows) via the access point, it gets an IP address of 192.168.0.201, and everything works perfectly, so I'm pretty happy that PC1 is working as its meant to.

 

Right, onto PC2.

 

PC2 has two NICs, both of which have been used on linux and windows before, so I dont think theres any compatability problems. when i connected the first NIC of PC2 to PC1, nothing happens, no activity lights, no dhcp info on PC2, and needless to say no connection. manually configuring PC2 (to 192.168.2.2) yeilds the same result. Mandriva recognises and configures the NIC fine, but it does nothing.

 

the second NIC does one of three things (seeming randomly). either the same as the first NIC, no IP address, no connection. Or, it recieves its address via DHCP, but then cannot ping anything other than itself. Or, it recieves its address, takes a few minutes before it can ping anything, and then the connection works fine (can ping everything, DNS works, internet works), but the connection is very slow (not even fast enough to stream MP3s from PC1).

 

I have just attempted an alternative configuration, that is plugging my laptop into the wired NIC on PC1 (incase this was somehow at fault), but my laptop receives an IP of 192.168.2.201 and everything works fine, and at full speed. So once again i'm quite happy with PC1's configuration and I think the problem lies with PC2.

 

I currently have a working (but slow) connection on PC2, and this is what it looks like

 

ifconfig eth1
eth1   Link encap:Ethernet  HWaddr 00:50:8D:D5:D0:3D
	  inet addr:192.168.2.253  Bcast:192.168.2.255  Mask:255.255.255.0
	  inet6 addr: fe80::250:8dff:fed5:d03d/64 Scope:Link
	  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
	  RX packets:2580 errors:0 dropped:0 overruns:0 frame:0
	  TX packets:3892 errors:1 dropped:0 overruns:0 carrier:0
	  collisions:0 txqueuelen:1000
	  RX bytes:1489893 (1.4 MiB)  TX bytes:375431 (366.6 KiB)
	  Interrupt:4 Base address:0xc000

cat /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes
METRIC=10

 

I will post similar details for the other occurances when they next crop up, in the mean time does anyone have a clue what could be going on? or even better, how to fix it?!

 

Many Thanks,

 

Owen Mc

Edited July 18, 2006 by omcaree

[coverup]

If this interface is eth1, shouldn't the first line then be

DEVICE=eth1

First, try running network interfaces one at a time, and check routing table for each of them by executing as root

route -n

[omcaree]

Correction, the first line is eth1 (eth0 has exactly the same config, and i opened the wrong file!)

 

For the working (but slow), connection i get this:

 

# route -n
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	 10	 0		0 eth1
127.0.0.0	   0.0.0.0		 255.0.0.0	   U	 0	  0		0 lo
0.0.0.0		 192.168.2.1	 0.0.0.0		 UG	10	 0		0 eth1

 

Which looks ok to me?

 

for the non working config I get this:

 

route -n
Kernel IP routing table
Destination	 Gateway		 Genmask		 Flags Metric Ref	Use Iface
127.0.0.0	   0.0.0.0		 255.0.0.0	   U	 0	  0		0 lo

 

Which just proves that it isn't working? despite the fact that Mandriva can see the card, and configure it. It doesn't get an IP and so it cant see anything.

 

manuallying configuring the non-working config yeilds this:

 

ifconfig eth3
eth3	  Link encap:Ethernet  HWaddr 00:0F:B5:06:55:16
	  inet addr:192.168.2.2  Bcast:192.168.2.255  Mask:255.255.255.0
	  inet6 addr: fe80::20f:b5ff:fe06:5516/64 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:5 Base address:0xa000

 

(note that the card has now become eth3 since i have removed it and replaced it again. I enabled my firewire devices which have taken up eth0 and eth2)

 

route -n
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 eth3
127.0.0.0	   0.0.0.0		 255.0.0.0	   U	 0	  0		0 lo

 

and pinging the gateway:

ping 192.168.2.1
PING 192.168.2.1 (192.168.2.1) 56(84) bytes of data.
From 192.168.2.2 icmp_seq=1 Destination Host Unreachable
From 192.168.2.2 icmp_seq=2 Destination Host Unreachable

[omcaree]

Further to my last post, I performed route -n on PC1 and saved it to a shared folder. and here is the output of that (eth2 being connected to the internet, eth1 being the wired connection and eth0 being the wireless access point), and 192.168.1.254 being the address of the router/modem.

 

Kernel IP routing table
Destination	 Gateway		 Genmask		 Flags Metric Ref	Use Iface
255.255.255.255 0.0.0.0		 255.255.255.255 UH	0	  0		0 eth0
192.168.2.0	 0.0.0.0		 255.255.255.0   U	 10	 0		0 eth1
192.168.1.0	 0.0.0.0		 255.255.255.0   U	 0	  0		0 eth2
192.168.0.0	 0.0.0.0		 255.255.255.0   U	 10	 0		0 eth0
0.0.0.0		 192.168.1.254   0.0.0.0		 UG	0	  0		0 eth2

 

I have shorewall masquerading connections between the internet (eth2) and the other two interfaces.

[coverup]

it looks to me as a routing problem. When you configure the interface manually, you must also define the gateway for the interface (which is not defined according to your post). If you start the device on boot, the file /etc/sysconfig/network must include

HOSTNAME=the-host-name
NETWORKING=yes
GATEWAY=192.168.2.1
GATEWAYDEV=eth3

If you start eth3 manually, run this command after the interface is started

/sbin/route add default gw 192.168.2.1 dev eth3

[omcaree]

Today I installed a wireless NIC in my PC and thats working fine now, but I just tested the configuration given by coverup and that seems to have worked too.

 

Many thanks for the sollution, it would have bugged me otherwise