Destination Host Unreachable

haydn.storr · 09-23-2011, 07:13 AM

Hi,

I'm trying to get a second network interface setup on our linux server so it can connect to the internal backup network.

eth0 is the primary network interface LAN/WAN and is/has been working fine.

eth1 has never been used before. We ran the cables in yesterday for this interface, cables are known to be good. Our backup LAN is on 10.0.5.x

I setup the IP add for eth1 but can't ping any other machines on the 10.0.5.x network. Other machines on the 10.0.5.x can't ping the linux box.

All 10.0.5.x machines run to a single switch and all ports have been put in the same VLAN. Ports have been to set 1000/full on the switch.

[root] /etc/sysconfig/network-scripts # ifconfig
eth0 Link encap:Ethernet HWaddr 00:0F:20:30:F1:42
inet addr:217.77.1.xxx Bcast:217.77.1.xxx Mask:255.255.255.224
inet6 addr: fe80::20f:20ff:fe30:f142/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:16659255 errors:0 dropped:0 overruns:0 frame:0
TX packets:15376555 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:872423270 (832.0 MiB) TX bytes:1300339376 (1.2 GiB)
Interrupt:209 Memory:f7cf0000-f7d00000

eth1 Link encap:Ethernet HWaddr 00:0F:20:30:F1:41
inet addr:10.0.5.100 Bcast:10.0.5.255 Mask:255.255.255.0
UP BROADCAST MULTICAST 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:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
Interrupt:217 Memory:f7ce0000-f7cf0000

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:5215187 errors:0 dropped:0 overruns:0 frame:0
TX packets:5215187 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:912282098 (870.0 MiB) TX bytes:912282098 (870.0 MiB)

[root] /etc/sysconfig/network-scripts # netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
217.77.1.xxx 0.0.0.0 255.255.255.224 U 0 0 0 eth0
10.0.5.0 10.0.5.100 255.255.255.0 UG 0 0 0 eth1
10.0.5.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 217.77.1.xxx 0.0.0.0 UG 0 0 0 eth0
[root] /etc/sysconfig/network-scripts # ping 10.0.5.4
PING 10.0.5.4 (10.0.5.4) 56(84) bytes of data.
From 10.0.5.100 icmp_seq=2 Destination Host Unreachable
From 10.0.5.100 icmp_seq=3 Destination Host Unreachable
From 10.0.5.100 icmp_seq=4 Destination Host Unreachable

--- 10.0.5.4 ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 4000ms
, pipe 3
[root] /etc/sysconfig/network-scripts #

Any advice would great.

Many thanks in advance.

ButterflyMelissa · 09-23-2011, 07:42 AM

Just a hint, are you pinging on eth0? Try this

Quote:

ping -I ethx [IP address]

where ethx is the card, eth0 is the first one, eth1 the second one ect...

Quote:

Other machines on the 10.0.5.x can't ping the linux box.

..of course, if the Linux box ignores Pings, there is no response...

Good luck

Thor

haydn.storr · 09-23-2011, 07:53 AM

Hi Thor,

Thanks for the taking the time to reply. Sadly still getting the same error:-

[root] /etc/sysconfig/network-scripts # ping -I eth1 10.0.5.4
PING 10.0.5.4 (10.0.5.4) from 10.0.5.100 eth1: 56(84) bytes of data.
From 10.0.5.100 icmp_seq=2 Destination Host Unreachable
From 10.0.5.100 icmp_seq=3 Destination Host Unreachable
From 10.0.5.100 icmp_seq=4 Destination Host Unreachable

Cheers

etech3 · 09-23-2011, 08:00 AM

Just as a test,

You may try switching eth1 to the same networks as eth0.
Then do your testing.

How do you know the network cables are good. Were they tested and scanned?

dilbert_uk · 09-23-2011, 08:02 AM

To see if it's a hardware problem you could connect the 10.0.5.x network to the other Ethernet card with eth0. Set eth0 then to 10.0.5.100 and try if this works.

haydn.storr · 09-23-2011, 08:08 AM

Hi,

I'm not in a position to get to the machine today, some 200miles away and I don't fancy the drive on a Friday afternoon! I have another 2 machines to set-up with a second network interface. I will try on those two machines and see what results I get. The network cables were tested before use with a scanner. I suspect it's something I'm doing wrong:-) If I try the other 2 machines and get the same problem with all 3 then I know I'm at fault somewhere along the line!

Cheers

haydn.storr · 09-23-2011, 08:39 AM

Well second machine is doing the same as the fist so I've posted the commands as I ran them on the second box. I must admit I don't understand where I'm going wrong, unless networks haven't set the switch ports in the same vlan.

cheers

-bash-3.2# ifconfig eth1 10.0.5.101 netmask 255.255.255.0 up
-bash-3.2# ifconfig
eth0 Link encap:Ethernet HWaddr 00:18:FE:FB:3E:E3
inet addr:217.77.x.x Bcast:217.77.x.x Mask:255.255.255.24 0
inet6 addr: fe80::218:feff:fefb:3ee3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:351982426 errors:0 dropped:0 overruns:0 frame:0
TX packets:351728424 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:100241072999 (93.3 GiB) TX bytes:117584840807 (109. 5 GiB)
Interrupt:209

eth1 Link encap:Ethernet HWaddr 00:18:FE:FB:3E:E2
inet addr:10.0.5.101 Bcast:10.0.5.255 Mask:255.255.255.0
inet6 addr: fe80::218:feff:fefb:3ee2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:176 (176.0 b)
Interrupt:217

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:4538990331 errors:0 dropped:0 overruns:0 frame:0
TX packets:4538990331 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1043191291789 (971.5 GiB) TX bytes:1043191291789 (9 71.5 GiB)

-bash-3.2# route add -net 10.0.5.0 netmask 255.255.255.0 eth1

-bash-3.2# ping -I eth1 10.0.5.4
PING 10.0.5.4 (10.0.5.4) from 10.0.5.101 eth1: 56(84) bytes of data.
From 10.0.5.101 icmp_seq=2 Destination Host Unreachable
From 10.0.5.101 icmp_seq=3 Destination Host Unreachable
From 10.0.5.101 icmp_seq=4 Destination Host Unreachable

--- 10.0.5.4 ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 39 99ms
, pipe 3

-bash-3.2# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irt t Iface
217.77.x.x 0.0.0.0 255.255.255.240 U 0 0 0 eth0
10.0.5.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
10.0.5.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 217.77.x.x 0.0.0.0 UG 0 0 0 eth0

-bash-3.2# route add -net 10.0.5.0 netmask 255.255.255.0 gw 10.0.5.101 eth1

-bash-3.2# ping -I eth1 10.0.5.4
PING 10.0.5.4 (10.0.5.4) from 10.0.5.101 eth1: 56(84) bytes of data.
From 10.0.5.101 icmp_seq=2 Destination Host Unreachable
From 10.0.5.101 icmp_seq=3 Destination Host Unreachable
From 10.0.5.101 icmp_seq=4 Destination Host Unreachable

--- 10.0.5.4 ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3999ms
, pipe 3
-bash-3.2# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
217.77.x.x 0.0.0.0 255.255.255.240 U 0 0 0 eth0
10.0.5.0 10.0.5.101 255.255.255.0 UG 0 0 0 eth1
10.0.5.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
10.0.5.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 217.77.x.x 0.0.0.0 UG 0 0 0 eth0