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I have 2 devices :
- PC (debian 16.04) : 10.0.0.56
- Android device (4.4.2) : 10.0.0.38
They're on the same network, have the same gateway which is 10.0.0.1 but whenever I try to ping from one device to the other, I have a
PING 10.0.0.38 (10.0.0.38) 56(84) bytes of data.
From 10.0.0.56 icmp_seq=1 Destination Host Unreachable
The weird part is that I can still ping other devices (using wifi or not), in the same network with the 2 of them. What is causing this problem ?
When I run arp -a on my PC (10.0.0.56) I have an entry like this :
? (10.0.0.38) at <incomplete> sur wlp1s0
Also, I don't know how to disable the ARP firewall on my android device, there's no setting like this – Nabil B. – 2016-07-07T12:07:09.310First, sorry about my typo, I've edited the original answer to change the 10.0.0.56 to 10.0.0.38. According to your description, I'm sure that the android device has enabled the ARP firewall. I'm not sure if this setting can be changed by a user. Normally, we need root permission to change such settings. Also, I'm not familiar with the android device. As a network engineer, what I can say is that the ARP firewall is mechanism which prevent the host from responding to any ARP request, so that no one on the same subnet can initiate the connect to the host. It's for security reason. – Steven Lee - MSFT – 2016-07-08T05:55:37.963
Ok I'll search more about the arp firewall. But what I find weird, is that I can still ping other devices in my network with my android device. Also, yesterday the ping from my pc to android worked for a very short time and then got the same error – Nabil B. – 2016-07-08T08:08:41.400
The android device should be able to ping other device, it's normal. Because, it can get the MAC address of other device through ARP. – Steven Lee - MSFT – 2016-07-08T08:22:18.873
Did you ping the PC from the android device? If yes, it can be explained. Because, if the android device starts the communication to PC, it will expose its' MAC to PC, so that your PC are able to access the android device. But the arp entry is dynamic, which means that it will be aged and cleared. So, after a period, your PC can't ping the android again. ARP firewall is one possibility. Anything preventing the ARP response from the android will cause this issue. – Steven Lee - MSFT – 2016-07-08T08:26:48.580
If I ping my PC, I have the destination host unreachable error. I checked my arp table in the android device and there's no entry for my PC, if I add an entry myself, can it solve the problem ? – Nabil B. – 2016-07-08T09:09:14.387
If you manually add an entry, it will resolve the issue. If you still can't ping your PC, the error code should be different, such as Time Out. – Steven Lee - MSFT – 2016-07-08T09:19:28.453