[CLUE-Tech] network issue

[David Anselmi]

Jeffery Cann wrote:
[...]
> 
> eth0      Link encap:Ethernet  HWaddr 00:E0:98:88:7F:C3
>           inet addr:192.168.254.76  Bcast:255.255.255.255  Mask:255.255.255.0
>           UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:263 errors:0 dropped:0 overruns:0 frame:133
>           TX packets:114 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:100
>           RX bytes:42922 (41.9 Kb)  TX bytes:20738 (20.2 Kb)
>           Interrupt:3 Base address:0x300

Looks broke, I'm guessing that frame:133 means about half of your 
received packets are bad.  That shouldn't be.  Possible causes are 
network saturation (look at the collisions number on a busier machine) 
or hardware/cable problems.  You can also use netstat -i to get some 
error stats.

Are you using DHCP?  That would explain the delay when you run the 
network start script (DHCP takes a while to timeout, but errors would 
slow it down).

The broadcast address looks odd.  It should be 192.168.254.255.  Not 
sure it matters in you case though.  Looks like your net-tools are old, 
too.  Mine ifconfig (1.42) reports RX/TX bytes in KiB rather than Kb.

> 
>>From this laptop, I can connect to my server on the 192.168.254.x (LAN) 
> network.  The connection seems to work okay, but if I ping my local server, I 
> will lose packets.   If I ping various internet domains, I will receive 
> 'unknown host' errors.

This is because the DNS lookup packets are getting lost so ping can't 
find the IP address.

> I can then try the corresponding IP address and it 
> will mostly work, but I'll drop 20-30% of the packets.  BTW - My LAN is run 
> off of a firewall / router running NAT, connected to my AT&T broadband 
> account.

You might try tcpdump, ethereal, or iptables logging to see if the 
firewall sees the bad packets.  Run it on both laptop and firewall and 
see if (for example) dns replies show up on the firewall but not the 
laptop--then you'll know it is the laptop side that is bad.  It could 
also be that the firewall is mangling packets (bad card or bad cable).

I don't see an easy way to tell what speed your NIC is running--perhaps 
the driver says when it loads (in your kernel logs).  Perhaps the speed 
is wrong or autodetecting isn't working and you have to set it 
explicitly (see the driver docs).

Let us know what it is when you find it.

Dave