Get DHCP data but no network [Solved]

[vaettchen]

Weird problem:

After a complete "equo upgrade" yesterday (which moved me to the latest kernel 3.6 - great!), I started my machine this morning and have absolutely no network functionality anymore. In detail:

Initially, the network seems to work - I get an IP address and the correct nameservers.
I can

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ifconfig eth0 down
ifconfig eth0 up
dhcpcd eth0

and get all the right data, including the correct entries in /etc/resolv.conf.

BUT:

I can't even successfully

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ping localhost

it gives a 100% package loss (yes, it resolves to 127.0.0.1).
Obviously, internal network and the Internet are not reachable either - headache!

This is irrespective of the network interface, i.e. the same situation for eth0 and wlan0.

My machine is an AMD64 KDE - 6 yrs old but in perfect shape.

Thanks for any hint,
Rainer

[Fitzcarraldo]

What are the manufacturers and models of your wired and wireless network controllers? Have you checked using the lsmod command to see if their kernel modules are loaded?

Do the network controllers require firmware (micro code)? Is the latest version of their firmware package installed? Is the firware for your network controllers provided by the package sys-kernel/linux-firmware? If it is, is the latest version of that package installed?

Did you do also try equo update && equo upgrade && equo conf update afterwards?

What happens if you enter the command dhclient and then try pinging e.g. http://www.cisco.com?

[vaettchen]

Thanks, Fitzcarraldo, for trying to help me so early in the morning!

Here the relevant lines from lspci:

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02:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02)
06:0b.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8169 PCI Gigabit Ethernet Controller (rev 10)

And her what I believe is relevant from lsmod:

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r8169                  39896  0
iwl3945                41930  0
iwlegacy               38634  1 iwl3945
mac80211              215476  2 iwl3945,iwlegacy
cfg80211              137752  3 iwl3945,iwlegacy,mac80211

The question in respect of firmware I can't answer (would need more instructions / research to find out where to look) but both network controllers seem to work find since they seem to communicate in the early stage with the DHCP server. I tried deleting /etc/resolv.conf - it was properly rebuilt after eth0 down / up again.
Also, these interfaces work since ages without any problem, and they also work with the latest Daily Live DVD.

Using dhclient and then ping http://www.cisco.com yields no result - no response at all after entring the command, and upon <Ctrl C> back to the command prompt, without any output.

Did you do also try equo update && equo upgrade && equo conf update afterwards?

I'm sure that I did equo conf update yesterday after the upgrade. This is consistent with the "All fine baby, nothing to do" message I get now when I try this again.

I'm pretty sure that I tried another equo update yesterday after the first run (initially, there was a problem with the nvidia driver, so I fumbled a bit and got it resolved). But, to the best of my memory, this yielded no further updates, and then I certainly skipped the second equo upgrade.

EDIT

Here the response to ifconfig which seems to indicate that communication has taken place at some point:

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eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.100  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::290:f5ff:fe58:471  prefixlen 64  scopeid 0x20<link>
        ether 00:90:f5:58:04:71  txqueuelen 1000  (Ethernet)
        RX packets 1375  bytes 173697 (169.6 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1376  bytes 149482 (145.9 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 16436
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 512  bytes 33128 (32.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 512  bytes 33128 (32.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[vaettchen]

It is a firewall issue - found it out looking at dmesg. I have simply

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ufw disable

and the problem is gone. I'll try to find out more. I did a

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ufw allow 22

yesterday and this has possibly disabled all other ports? I have no experience with firewalls, so have to do some study.

I mark this as resolved.

Thanks for trying to help me!

[Fitzcarraldo]

Good to know you found the source of the problem. If you use SAMBA, the following might be helpful:

How to config ufw/ufw-frontends for Samba browsing/printing