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I am working on an embedded linux board with a freescale cpu and an ltib built linux on it. The appliance has two network interfaces and here is the output of ifconfig and route commands:

[root@sina-dwdm /root]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:00:00:00:00:05
          inet addr:110.122.5.0  Bcast:110.122.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b)  TX bytes:420 (420.0 b)
          Base address:0x4000

eth1      Link encap:Ethernet  HWaddr 00:00:00:01:00:05
          inet addr:192.168.5.0  Bcast:192.168.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:20530 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8622 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2052409 (1.9 Mb)  TX bytes:1066396 (1.0 Mb)
          Base address:0xc000

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:59 errors:0 dropped:0 overruns:0 frame:0
          TX packets:59 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:5294 (5.1 Kb)  TX bytes:5294 (5.1 Kb)

[root@sina-dwdm /root]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
110.122.0.0     *               255.255.0.0     U     0      0        0 eth0
192.168.0.0     *               255.255.0.0     U     0      0        0 eth1
127.0.0.0       *               255.0.0.0       U     0      0        0 lo

When i try pinging this board from my computer on 192.168.1.194 or ping my computer from the board there is no success. But there are other computers on the same subnet as my computer which can ping the board some of them are also pingable! from board and some not. And more puzzling for me is that even those that are not pingable from board can telnet to it. (but not my computer)

There is no firewall on my computer and my computer and other nodes on network see each other. Rebooting the board makes no change. And here is the output of arp command on the board after pinging my computer: (It is successful)

[root@sina-dwdm /root]# arp
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.1.201            ether   2c:56:dc:3d:ac:e1   C                     eth1
192.168.1.54             ether   00:0c:29:65:ac:39   C                     eth1
192.168.1.195            ether   40:16:7e:e7:5b:5f   C                     eth1
192.168.1.194            ether   10:c3:7b:91:39:92   C                     eth1

Where can i look for source of problem?

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    Are you sure 192.168.0.0 is a /16 network? If the other machines have it configured as 192.168.1.0/24 (which is more usual), then your 192.168.5.0 on eth1 would just get ignored, and therefore no pings. You also got a static IP address in a /16 from China TieTong Telecom? They seem to have reserved enough IPs, but that's also unusal. – dirkt May 20 '17 at 15:05
  • Thank you @dirkt it solved the problem. my computer subnet mask was 255.255.255.0 and this was the source of error. actually i was changed my ipv4 settings to dhcp on my computer for some reason and... – mhk May 20 '17 at 15:11
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(Written up as answer after confirmation).

Are you sure 192.168.0.0 is a /16 network? If the other machines have it configured as 192.168.1.0/24 (which is more usual), then your 192.168.5.0 on eth1 would just get ignored, and therefore no pings.

Change the netmask to 255.255.255.0 for a /24 subnet on this computer, or change the netmask to 255.255.0.0 for a /16 subnet on the other computers, and see if that fixes it.

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