Multiple NIC, no ping

November 16, 2017 1k views
Networking Ubuntu 16.04

Ubuntu server 16.04, fresh install on x64.
Here the topology:

internet router ( ---- enp0s7 (
host ( ----- enp1s8 (

Internet works ok but I can't ping, only arp ping.

/etc/network/interfaces (note the comments):

The primary network interfaceauto enp0s7

iface enp0s7 inet static

The GRAF net network interface

auto enp1s8
iface enp1s8 inet static


metric 400

up route add -net dev enp1s8

results from route -n:

Destination Gateway Genmask Flags Metric Ref Use Iface UG 0 0 0 enp0s7 U 0 0 0 enp1s8 U 0 0 0 enp0s7

results from arp-scan on enp1s8 interface:

Interface: enp1s8, datalink type: EN10MB (Ethernet)
Starting arp-scan 1.8.1 with 256 hosts ( 00:0c:42:fa:05:e2
1 packets received by filter, 0 packets dropped by kernel
Ending arp-scan 1.8.1: 256 hosts scanned in 1.453 seconds (176.19 hosts/sec). 1 responded

I think doesn't matter but ipforward is YES.

Why I can't reach on level 3 host What I'm doing wrong?
I think for what I know and what I read on the web this is the right configuration...doesn't work also uncommenting "up route add -net dev enp1s8"

1 Answer is a local only subnet so you won't be able to ping out or in to it.

Only other hosts on the same subnet would be able to ping each other. That is why you are having the issue.

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