Nejprve prozkoumáme svoji aktuální konfiguraci.

Síťová rozhraní na počítači si zjistíme příkazem link list

pikara:~$ /sbin/ip link list
1: lo: <LOOPBACK,UP> mtu 3924 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: brg0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether fe:fd:00:00:15:b8 brd ff:ff:ff:ff:ff:ff
3: tunl0@NONE: <NOARP> mtu 1480 qdisc noop
    link/ipip 0.0.0.0 brd 0.0.0.0
4: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:03:47:3b:25:b0 brd ff:ff:ff:ff:ff:ff
5: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:03:47:3b:25:b1 brd ff:ff:ff:ff:ff:ff
6: eth2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 100
    link/ether 00:d0:b7:00:ca:51 brd ff:ff:ff:ff:ff:ff
7: eth3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 100
    link/ether 00:d0:b7:00:ca:52 brd ff:ff:ff:ff:ff:ff
8: tun0@NONE: <POINTOPOINT,NOARP,UP> mtu 1480 qdisc noqueue
    link/ipip 0.0.0.0 peer 192.168.199.6

Aktuální adresy rozhraní. zjistíme

pikara:~$ /sbin/ip address show
1: lo: <LOOPBACK,UP> mtu 3924 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
2: brg0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether fe:fd:00:00:15:b8 brd ff:ff:ff:ff:ff:ff  
3: tunl0@NONE: <NOARP> mtu 1480 qdisc noop
    link/ipip 0.0.0.0 brd 0.0.0.0
4: eth0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:03:47:3b:25:b0 brd ff:ff:ff:ff:ff:ff   
    inet 192.168.199.2/30 brd 192.168.199.3 scope global eth0
5: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 100
    link/ether 00:03:47:3b:25:b1 brd ff:ff:ff:ff:ff:ff
    inet 10.16.66.51/19 brd 10.16.127.255 scope global eth1
6: eth2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 100
    link/ether 00:d0:b7:00:ca:51 brd ff:ff:ff:ff:ff:ff
7: eth3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 100
    link/ether 00:d0:b7:00:ca:52 brd ff:ff:ff:ff:ff:ff
8: tun0@NONE: <POINTOPOINT,NOARP,UP> mtu 1480 qdisc noqueue
    link/ipip 0.0.0.0 peer 192.168.199.6
    inet 10.16.66.51/32 scope global tun0

Směrovací tabulku. nám pak ukáže

pikara:~$ /sbin/ip route show
192.168.199.0/30 dev eth0  proto kernel  scope link  src 192.168.199.2
192.168.199.4/30 via 192.168.199.1 dev eth0  
10.16.64.0/19 dev eth1  proto kernel  scope link  src 10.16.66.51
10.32.64.0/19 via 192.168.199.6 dev tun0 onlink
10.48.0.0/13 via 10.16.66.60 dev eth1
10.32.0.0/13 via 192.168.199.1 dev eth0

ARP table. ARP/neighbor cache/table

pikara:~$ /sbin/ip neigh show
10.16.66.18 dev eth1 lladdr 00:90:27:f7:19:1e nud reachable
10.16.68.2 dev eth1 lladdr 00:b0:d0:16:21:12 nud reachable
192.168.199.1 dev eth0 lladdr 00:04:9a:41:0d:20 nud reachable    

Směrovací tabulky. 

pikara:~$ /sbin/ip rule list
0:      from all lookup local
32766:  from all lookup main
32767:  from all lookup default