00:00:5e:00:53:01 > 00:00:5e:00:53:02, ethertype IPv4 (0x0800), length 98: 192.0.2.1 > 192.0.2.2: ICMP echo request, id 37038, seq 3, length 64
00:00:5e:00:53:02 > 00:00:5e:00:53:01, ethertype IPv4 (0x0800), length 98: 192.0.2.2 > 192.0.2.1: ICMP echo reply, id 37038, seq 3, length 64
</pre>
*どうやって、MACアドレスを知るのか?一旦、MACアドレスのキャッシュをクリア
<pre>
$ sudo ip netns exec ns1 ip neigh flush all
</pre>
*icmp だけでなく、arpもダンプ対象に加える
<pre>
$ sudo ip netns exec ns1 tcpdump -tnel -i ns1-veth0 icmp or arp
</pre>
*再度ping
<pre>
$ sudo ip netns exec ns1 tcpdump -tnel -i ns1-veth0 icmp or arp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on ns1-veth0, link-type EN10MB (Ethernet), capture size 262144 bytes
00:00:5e:00:53:01 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.0.2.2 tell 192.0.2.1, length 28
00:00:5e:00:53:02 > 00:00:5e:00:53:01, ethertype ARP (0x0806), length 42: Reply 192.0.2.2 is-at 00:00:5e:00:53:02, length 28
00:00:5e:00:53:01 > 00:00:5e:00:53:02, ethertype IPv4 (0x0800), length 98: 192.0.2.1 > 192.0.2.2: ICMP echo request, id 37051, seq 1, length 64
00:00:5e:00:53:02 > 00:00:5e:00:53:01, ethertype IPv4 (0x0800), length 98: 192.0.2.2 > 192.0.2.1: ICMP echo reply, id 37051, seq 1, length 64
00:00:5e:00:53:01 > 00:00:5e:00:53:02, ethertype IPv4 (0x0800), length 98: 192.0.2.1 > 192.0.2.2: ICMP echo request, id 37051, seq 2, length 64
00:00:5e:00:53:02 > 00:00:5e:00:53:01, ethertype IPv4 (0x0800), length 98: 192.0.2.2 > 192.0.2.1: ICMP echo reply, id 37051, seq 2, length 64
00:00:5e:00:53:01 > 00:00:5e:00:53:02, ethertype IPv4 (0x0800), length 98: 192.0.2.1 > 192.0.2.2: ICMP echo request, id 37051, seq 3, length 64
00:00:5e:00:53:02 > 00:00:5e:00:53:01, ethertype IPv4 (0x0800), length 98: 192.0.2.2 > 192.0.2.1: ICMP echo reply, id 37051, seq 3, length 64
00:00:5e:00:53:02 > 00:00:5e:00:53:01, ethertype ARP (0x0806), length 42: Request who-has 192.0.2.1 tell 192.0.2.2, length 28
00:00:5e:00:53:01 > 00:00:5e:00:53:02, ethertype ARP (0x0806), length 42: Reply 192.0.2.1 is-at 00:00:5e:00:53:01, length 28
</pre>