root@radionet-nas:/var/log# tcpdump -vvvv -n -i wlan0 port 6668 and host 192.168.4.156
tcpdump: listening on wlan0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
20:43:34.476752 IP (tos 0x0, ttl 64, id 35370, offset 0, flags [DF], proto TCP (6), length 64)
192.168.4.144.35531 > 192.168.4.156.6668: Flags [P.], cksum 0xf6a7 (correct), seq 2902280087:2902280111, ack 9053, win 65535, length 24
20:43:34.639317 IP (tos 0x0, ttl 255, id 1295, offset 0, flags [none], proto TCP (6), length 68)
192.168.4.156.6668 > 192.168.4.144.35531: Flags [P.], cksum 0x058a (correct), seq 1:29, ack 24, win 1886, length 28
20:43:34.867394 IP (tos 0x0, ttl 64, id 35371, offset 0, flags [DF], proto TCP (6), length 40)
192.168.4.144.35531 > 192.168.4.156.6668: Flags [.], cksum 0x685a (correct), seq 24, ack 29, win 65535, length 0