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Old 11-17-2011, 01:58 PM   #1
tezarin
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Host not reachable - Very strange


Hi all,

I have an Ubuntu machine which is connected to two switches, IDMZ and ODMZ. The firewall is also connected to the ODMZ switch. Firewall address is 192.168.1.1. This Ubuntu box has two network cards.

The machine can be reached from a 63. address but should be able reachable via a 192. address while inside the firewall. The problem is it can ping yahoo.com just fine but can't ping another machine in the same network or even the default gateway: 192.168.1.1

Here are some outputs:

Code:
ifconfig -a
eth0      Link encap:Ethernet  HWaddr 90:e6:ba:3c:77:7d
          inet addr:192.168.1.13  Bcast:192.168.1.255  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:35 Base address:0xa000

eth1      Link encap:Ethernet  HWaddr 00:a0:cc:62:34:d5
          inet addr:63.x.x.x  Bcast:63.x.x.x  Mask:255.255.255.128
          inet6 addr: fe80::2a0:ccff:fe62:34d5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:8024 errors:4 dropped:0 overruns:0 frame:0
          TX packets:436 errors:7 dropped:0 overruns:0 carrier:7
          collisions:0 txqueuelen:1000
          RX bytes:505698 (505.6 KB)  TX bytes:53709 (53.7 KB)
          Interrupt:16 Base address:0xe800

eth2      Link encap:Ethernet  HWaddr 00:14:d1:1e:9a:31
          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:17 Base address:0x2800

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:48 errors:0 dropped:0 overruns:0 frame:0
          TX packets:48 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:5032 (5.0 KB)  TX bytes:5032 (5.0 KB)
Code:
uname -rvo
2.6.32-21-server #32-Ubuntu SMP Fri Apr 16 09:17:34 UTC 2010 GNU/Linux


route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
63.x.x.x     *               255.255.255.128 U     0      0        0 eth1
192.168.1.0     *               255.255.255.0   U     0      0        0 eth0
default         192.168.1.1     0.0.0.0         UG    100    0        0 eth0
default         gateway.[half of the domain name here] 0.0.0.0         UG    100    0        0 eth1
Code:
arp -n
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.1.5                         (incomplete)                                   eth0
192.168.1.1                         (incomplete)                                   eth0
63.x.x.x             ether   00:1e:8c:0d:b5:3a   C                      eth1
63.x.x.x              ether   00:0d:48:26:43:76   C                       eth1

 

route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
63.x.x.x     0.0.0.0         255.255.255.128 U     0      0        0 eth1
192.168.1.0     0.0.0.0         255.255.255.0    U     0      0       0 eth0
0.0.0.0         192.168.1.1     0.0.0.0             UG   100    0       0 eth0

If I try to ping outside of the firewall, it works just fine but if I ping a box which is located inside the firewall, it won't work:

Code:
PING 192.168.1.5 (192.168.1.5) 56(84) bytes of data.
From 192.168.1.13 icmp_seq=1 Destination Host Unreachable
From 192.168.1.13 icmp_seq=2 Destination Host Unreachable
From 192.168.1.13 icmp_seq=3 Destination Host Unreachable
Can someone please help me figure this out? I would really appreciate it.

Thanks,
Tezarin
 
Old 11-17-2011, 06:02 PM   #2
kbp
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Quote:
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)
You're not seeing any packets sent or received, can you try 'ethtool eth0' to see if it's actually connected ?
 
Old 11-21-2011, 08:10 AM   #3
tezarin
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Posts: 133

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Quote:
Originally Posted by kbp View Post
You're not seeing any packets sent or received, can you try 'ethtool eth0' to see if it's actually connected ?
Kbp,
Thanks for your reply. I checked and looks like I don't have ethtool installed on this server. Tried to install it but it got stuck on: 0% [Connecting to us.archive.ubuntu.com (91.189.92.176)]. But maybe this helps: All these machines are connected, the backup server has to network interfaces, one is connected to an IDMZ switch and the other one to a ODMZ switch. I tried a different port on the switch and still no luck. The machine cannot see/connect to anything within my domain 192.x.x.x but everything used to be OK. eth0 is up, please help me figure this out....Thanks
 
Old 11-23-2011, 08:37 AM   #4
tezarin
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Anyone? Please, I would appreciate it if someone help me figure this out.
 
Old 12-06-2011, 11:43 AM   #5
tezarin
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I did some more research and found out some more relative threads in which users had difficulty with two NICs.

What I was trying to say was my Ubuntu box has two NIC, each is connected to a switch. One can see outside of the firewall which is working fine. The other one is supposed to be able to see inside the firewall. The default gateway is 192.168.1.1 which the box cannot see it.

Therefore all the machines inside the firewall, cannot access this Ubuntu box...I'm guessing something needs to be turned on, such as IP forwarding, etc. i tried:

Code:
sysctl -w net.ipv4.ip_forward=1
but no luck.

This is the output of route -n:

Code:
root@servername:/usr/bin# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
63.x.x.0        0.0.0.0         255.255.255.128 U     0      0        0 eth1
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         63.x.x.1        0.0.0.0         UG    100    0        0 eth1
0.0.0.0         192.168.1.1     0.0.0.0         UG    100    0        0 eth0
Would someone please help me with this?

Thanks,
t

Last edited by tezarin; 12-06-2011 at 11:52 AM.
 
Old 12-07-2011, 06:32 AM   #6
zooppoop
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Like the previous guy posted you most likely don't have a link on your interface. or you have it plugged into the wrong device. That interface is not seeing any traffic. Check your cabling. If you don't have ethtool try tailing the message log or where ever your Kernel message go to after unplugging it and plugging it back in.

You also have configuration issues.

You have two default routes configured. You are only going to be able to use one choose the right network and set it.
 
  


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