unable to ping eth0 or localhost

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

Hi,
I have a machine running gentoo, and suddenly since a reboot I cannot ping eth0 or localhost ie both the machine's ip and localhost (127.0.0.1) don't ping. The network card on the machine is a dec chip/tulip.
What could be the reason and how to solve it.
I've recompiled the kernel, more than once but the problem persists.

I can boot from the gentoo cd and networking works in that case.

nephros · Posted: Tue Jan 23, 2007 10:34 am Post subject:

what does "ifconfig -a" produce?

What output do you get from running "/etc/init.d/net.eth0 restart"?
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mjrosenb · Posted: Tue Jan 23, 2007 10:37 am Post subject:

also what's the output of route?
warning, running route may take a while
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nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

I've just tried a different ethernet card and I have the same results. This card shows up as eth1 now.

Meanwhile this is the output of ifconfig -a:

dummy0 Link encap:Ethernet HWaddr D2:F4:CD:0C:4C:3C
BROADCAST NOARP 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:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)

eth1 Link encap:Ethernet HWaddr 00:C0:26:26:77:47
inet addr:<machines IP> Bcast:x.x.x.255 Mask:255.255.255.224
UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1
RX packets:20478 errors:0 dropped:0 overruns:0 frame:0
TX packets:351 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1249665 (1.1 Mb) TX bytes:24826 (24.2 Kb)
Interrupt:10 Base address:0xbc00

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:194 errors:0 dropped:0 overruns:0 frame:0
TX packets:194 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:15928 (15.5 Kb) TX bytes:15928 (15.5 Kb)

Output of restarting net.eth1:
Stopping eth1
Bringing down eth1
Shutting down eth1 ... ok
Starting eth1
Bringing up eth1
<ip address> ok
Adding routes
default via <default gateway ip> ...

This is the routing table (route -n):
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
x.x.x.0 0.0.0.0 255.255.255.224 U 0 0 0 eth1
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 <default gateway ip> 0.0.0.0 UG 0 0 0 eth1

What could be wrong?

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

what error does the ping command give?

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

If I ping 127.0.0.1,
I get
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.

--- 127.0.0.1 ping statistics ---
9 packets transmitted, 0 received, 100% packet loss, time 7999ms

(I had to press ^C)

The result is the same with pinging the ip address of the ethernet card only the time in ms is different.

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

do you have a firewall enabled?

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

One of the things I tried before posting here was to boot the 2006.1 minimal gentoo cd and I reinstalled it.
The problem remained the same.

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

I thought of that too.
No iptables/netfilter isn't set in the kernel on the machine.

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

Any ideas why I can't ping localhost and I can't ping the network card (even when I replace the card with one of a different make)?

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

I went to /proc/sys/net/ipv4
and noticed icmp_ignore_all was set to 1.

I edited this to 0 and now I can ping everything.

I'm not sure where this got set in the kernel or somewhere else.
I guess I'll do a search again this time on this.
Edit: didn't get any results. that's odd.

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E

melinux · n00b Joined: 25 May 2006 Posts: 59 Location: Malta

Hi, like I said above, now I found a quick fix at least.
Enabling that kernel setting (icmp_ignore_all was set to 1, I changed it to 0) allows me to ping everything I want now..

Though I think rebooting will mean I'll have to reset it. I'll have to add it to a script probably as I don't think this is covered in sysctl.conf...
If anyone has any idea where to set it permanently, that would be great.
Once I have that info I'll mark the thread as solved...

nielchiano · Veteran Joined: 11 Nov 2003 Posts: 1287 Location: 50N 3E