I have been researching this issue for a few weeks now, and I have not found much luck. The most general problem is that the Debian system that I have newly installed will not connect to the internet after the initial installation. I have tried several fresh installs from different install images, and all have the same result: the system will connect during installation, but will fail to connect as soon as it does its first HD boot.

(On a side note, the same system previously ran Debian Sarge without any issue. No changes have been made to the NIC or any other system component. Furthermore, Lenny is installed as a fresh install. It is not an upgrade from Sarge.)

In addition to trying several installation images, I have also tried the following:

CONFIRMED THE NIC - I have confirmed that my LAN card is operational by using it successfully in other systems and swapping it for other cards that have also been proven on other systems. The cards are all CNet PRO200WL PCI Fast Ethernet Adapters and have been proven as Debian compatible on Sarge installations.

CONFIRMED THE PCI SLOT - I have run lspci and confirmed that they system recognizes the card. It recognizes the CNet PRO200WL PCI Fast Ethernet Adapter as "02:02.0 Ethernet controller: Davicom Semiconductor, Inc. 21x4x DEC-Tulip compatible 10/100 Ethernet (rev 31)"

CONFIRMED THE ROUTER AND CAT-5 CABLE - the CAT-5 has been swapped with other functional systems, and the router has assigned an IP address to the system dynamically (proving that a successful connection has occurred at least once). This IP assignment is viewed both in the Debian system and on the router's DHCP list. The router currently functions with two other systems accessing the internet through it, and does not have any blocking or firewall enabled.

PING - Used ping to attempt connection to local machine, router, and WAN. Successful connection to local machine (assumed through local loopback) and Failed connections to router and WAN.

From this it seems that the system recognizes the card but fails to operate it, which implies to me a problem with the driver. However, the driver is present on the installation disk and is used without issue to perform a net-install. I am not clear what might happen between the CD boot and the HD boot that might cause this functionality to cease.

Some of the other articles that I have read suggest that it might be fixed by installing a DNS-Server on the localhost and referencing it instead of the router. Similar lines have suggested disabling IPv6. I have tried the latter of these two suggestions with no success (the system now has IPv6 enabled again). I do not think that the DNS would be the solution, because the problem seems to be with communication and not domain name mapping. To avoid using DNS services, I have been using IP addresses only in my attempts to correct the system troubles.

Please help!

Kind regards,

Jared Clemence

What does your ifconfig output look like ?

Thank you, dxqcanada, for looking into this for me. The output is as follows:

eth0 Link encap:Ethernet HWaddr 00:08:a1:0a:98:f9
inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::208:a1ff:fe0a:98f9/64 Scope:Link
UP BROADCAST MULTICAST MTU: 1500 Metric:1
RX packets:38 errors:4 dropped:0 overruns:0 frame:0
TX packets:62 errors:4 dropped:0 overruns:0 carrier:4
collisions:0 txqueuelen:1000
RX bytes:11464 (11.1 KiB) TX bytes:5344 (5.2 KiB)
Interrupt:18 Base address:0xd800

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:117 errors:0 dropped:0 overruns:0 frame:0
TX packets:117 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8222 (8.0 KiB) TX bytes:8222 (8.0 KiB)

--------------------
What are your thoughts?

-Jared

I would start by disabling ip6. Unless you are actually using it ?

http://www.debian-administration.org/articles/409

I see your IP address is 192.168.0.102 -- can you ping that address successfully?
Can you do "route" to see the routing table and get the Default Gateway?
If so, can you then ping the default gateway?

Finally can you browse the Internet by IP address rather than URL??

If you can do "cat /etc/resolv.conf" you should see the IP addresses if your nameservers. Can you ping those IP addresses?

I disabled ipv6 again, and like the first time, it didn't seem to fix the problem. ifconfig now reports the following:

I tried "ping 192.168.0.102" with success:
I used "route" with the following reported:

And "ping 192.168.0.1" to the gateway returns five "Destination Host Unreachable" errors and the following summary:

What do you think?

Oh! I forgot to report that the output of "cat /etc/resolv.conf" is:

And, pinging those addresses has the same result as pinging anything other than the host machine: for the IP address and Which is not too surprising though, because if I cannot ping 192.168.0.1 or 74.14.205.100, then I don't think that I would have access to a name server to resolve an address like hsd1.nj.comcast.net.

packet capture maybe ?

aptitude update
aptitude install tcpdump

open two terminal windows run tcpdump in one and then ping the router in the other..

Strange stuff:
You can pull an IP address from your router and your interface shows as UP but you can not ping the router that is giving you your IP address.
can you browse to the router at 192.168.0.1 or your comcast cable modem at 192.168.100.1

you could bypass the router just for test and hook directly to the comcast modem (need to POwercycle the modem so that it recognizes the new Mac address presented by your NIC and see if it pulls a public address then swap the router back in and go through the power cycle reset process so the comcast will again recognize the Routers Mac address and see if you can again pull a private address from the router.