installer does not find a network - but a live system does ... wtf?
Andi Meier
andimeier at gmx.net
Wed Mar 16 08:35:55 UTC 2011
In this post, I included the output of several networking related commands.
I would say, the most interesting output is that of ethtool, look at the last line:
- network unreachable: last line of ethtool output is:
Link detected: no
- network ok: last line of ethtool output is:
Link detected: yes
So, apparently the problem is on OSI layer 1 or 2, which renders all attempts to solve the problem on higher layers useless, IMHO. It is
important to state that it is not DHCP which is failing, but the network link is failing - which is in turn necessary for higher services
like DHCP etc.
However, I really don't understand WHY the problem exists.
BTW: I tried static IP as well, but to no avail, since there is no network available.
The following sections provide the output of the suggested commands which are:
- cat hostname
- cat /etc/network/interfaces
- route -n
- cat /etc/resolv.conf
- ifconfig -a
- ethtool eth0
- dhclient eth0
Those who are different when network is unreachable than when the network is up, are shown in both versions:
<<<<< cat hostname
koala
============================
<<<<< cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto eth0
iface eth0 inet dhcp
============================
<<<<< Network unreachable: route-n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
============================
<<<<< cat /etc/resolv.conf
nameserver 192.168.178.1
domain fritz.box
search fritz.box
============================
<<<<< Network unreachable: ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:26:18:f0:1d:43
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:4 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:240 (240.0 B) TX bytes:0 (0.0 B)
Interrupt:26 Base address:0xa000
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:46 errors:0 dropped:0 overruns:0 frame:0
TX packets:46 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:15721 (15.7 KB) TX bytes:15721 (15.7 KB)
============================
<<<<< Network ok: ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:26:18:f0:1d:43
inet addr:192.168.178.35 Bcast:192.168.178.255 Mask:255.255.255.0
inet6 addr: fe80::226:18ff:fef0:1d43/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:24 errors:0 dropped:0 overruns:0 frame:0
TX packets:60 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3348 (3.3 KB) TX bytes:7542 (7.5 KB)
Interrupt:26 Base address:0xa000
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:70 errors:0 dropped:0 overruns:0 frame:0
TX packets:70 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:19321 (19.3 KB) TX bytes:19321 (19.3 KB)
============================
<<<<< Network unreachable: ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Link partner advertised link modes: 10baseT/Half 10baseT/Full
Link partner advertised pause frame use: No
Link partner advertised auto-negotiation: Yes
Speed: 10Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0x00000033 (51)
Link detected: no
============================
<<<<< Network ok: ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Link partner advertised link modes: 10baseT/Half 10baseT/Full
Link partner advertised pause frame use: No
Link partner advertised auto-negotiation: Yes
Speed: 10Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0x00000033 (51)
Link detected: yes
============================
<<<<< Network unreachable: dhclient eth0
Internet Ssytems Consortium DHCP Client V3.1.3
...[some copyright output]...
Listening on LPF/eth0/00:26:18:f0:1d:41
Sending on LPF/eth0/00:26:18:f0:1d:41
Sending on Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 5
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 7
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 16
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 18
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 15
No DHCPOFFERS received.
No working leases in persistent database - sleeping.
============================
<<<<< Network ok: dhclient eth0
Internet Ssytems Consortium DHCP Client V3.1.3
...[some copyright output]...
Listening on LPF/eth0/00:26:18:f0:1d:41
Sending on LPF/eth0/00:26:18:f0:1d:41
Sending on Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3
DHCPOFFER of 192.168.178.35 from 192.168.178.1
DHCPREQUEST of 192.168.178.35 on eth0 to 255.255.255.255 port 67
DHCPACK of 192.168.178.35 from 192.168.178.1
bound to 192.168.178.35 -- renewal in 364413 seconds.
============================
*Finding:* apparently I can *always* get the system to work. I only have to do this one time after boot:
$ ifdown eth0 (output: "send_packet: Network is unreachable")
$ ifup eth0
Then, network is there. Everythings ok. Just one time this ifdown/ifup combination.
Also, the output of "ethtool eth0" is different before this ifdown/ifup combination and after it - different in 1 line:
before: Link detected: no
after: Link detected: yes
Seems the problem is on physical/link layer. Why is eth0 always down initially after boot and why does the ifdown/ifup combination always
cure the problem?
Andi
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