UPDATE
Okay, I performed some additional tests.
Client and Server are connected via wifi. Interfaces wlan0_0 (server), and wlan0 (client). Tunneling interfaces server side are tun0 for ipv4, and tun1 for ipv6. Tunneling interface client side is tun0.
Then I started OpenVPN connections, both ipv4 and ipv6, and recorded tcpdump output on server and client for the wifi and the tunneling interfaces (filtered for port 1194 to omit all the noise).
This is the result:
OpenVPN ipv4 connection, server, tcpdump -n -i wlan0_0 | grep 1194
23:44:39.070680 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 3964024372:3964024487, ack 238782141, win 32044, options [nop,nop,TS val 2904757 ecr 13106036], length 115
23:44:39.107613 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 115, win 32038, options [nop,nop,TS val 13107317 ecr 2904757], length 0
23:44:41.576609 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 115:294, ack 1, win 32044, options [nop,nop,TS val 2905384 ecr 13107317], length 179
23:44:41.576774 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 294, win 32038, options [nop,nop,TS val 13107934 ecr 2905384], length 0
23:44:41.604167 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 1:180, ack 294, win 32038, options [nop,nop,TS val 13107941 ecr 2905384], length 179
23:44:41.607639 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 180, win 32044, options [nop,nop,TS val 2905391 ecr 13107941], length 0
23:44:42.576680 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 294:473, ack 180, win 32044, options [nop,nop,TS val 2905634 ecr 13107941], length 179
23:44:42.602633 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 180:359, ack 473, win 32038, options [nop,nop,TS val 13108190 ecr 2905634], length 179
23:44:42.613033 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 359, win 32044, options [nop,nop,TS val 2905642 ecr 13108190], length 0
23:44:52.900623 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 359:474, ack 473, win 32038, options [nop,nop,TS val 13110765 ecr 2905642], length 115
23:44:52.905298 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 474, win 32044, options [nop,nop,TS val 2908216 ecr 13110765], length 0
23:44:52.906273 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 473:588, ack 474, win 32044, options [nop,nop,TS val 2908216 ecr 13110765], length 115
23:44:52.943598 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 588, win 32038, options [nop,nop,TS val 13110776 ecr 2908216], length 0
23:44:59.008891 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 474:605, ack 588, win 32038, options [nop,nop,TS val 13112292 ecr 2908216], length 131
23:44:59.047722 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 605, win 32044, options [nop,nop,TS val 2909752 ecr 13112292], length 0
23:45:02.263379 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 588:703, ack 605, win 32044, options [nop,nop,TS val 2910555 ecr 13112292], length 115
23:45:02.263593 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 703, win 32038, options [nop,nop,TS val 13113106 ecr 2910555], length 0
23:45:04.013057 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 605:736, ack 703, win 32038, options [nop,nop,TS val 13113543 ecr 2910555], length 131
23:45:04.013406 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 736:883, ack 703, win 32038, options [nop,nop,TS val 13113543 ecr 2910555], length 147
23:45:04.016260 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 736, win 32044, options [nop,nop,TS val 2910994 ecr 13113543], length 0
23:45:04.016941 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 883, win 32044, options [nop,nop,TS val 2910994 ecr 13113543], length 0
OpenVPN ipv4 connection, client, tcpdump -n -i wlan0 | grep 1194
23:44:39.070559 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 3964024372:3964024487, ack 238782141, win 32044, options [nop,nop,TS val 2904757 ecr 13106036], length 115
23:44:39.109685 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 115, win 32038, options [nop,nop,TS val 13107317 ecr 2904757], length 0
23:44:41.576423 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 115:294, ack 1, win 32044, options [nop,nop,TS val 2905384 ecr 13107317], length 179
23:44:41.578821 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 294, win 32038, options [nop,nop,TS val 13107934 ecr 2905384], length 0
23:44:41.607208 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 1:180, ack 294, win 32038, options [nop,nop,TS val 13107941 ecr 2905384], length 179
23:44:41.607238 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 180, win 32044, options [nop,nop,TS val 2905391 ecr 13107941], length 0
23:44:42.576407 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 294:473, ack 180, win 32044, options [nop,nop,TS val 2905634 ecr 13107941], length 179
23:44:42.609350 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 180:359, ack 473, win 32038, options [nop,nop,TS val 13108190 ecr 2905634], length 179
23:44:42.609430 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 359, win 32044, options [nop,nop,TS val 2905642 ecr 13108190], length 0
23:44:52.904997 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 359:474, ack 473, win 32038, options [nop,nop,TS val 13110765 ecr 2905642], length 115
23:44:52.905079 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 474, win 32044, options [nop,nop,TS val 2908216 ecr 13110765], length 0
23:44:52.905511 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 473:588, ack 474, win 32044, options [nop,nop,TS val 2908216 ecr 13110765], length 115
23:44:52.945665 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 588, win 32038, options [nop,nop,TS val 13110776 ecr 2908216], length 0
23:44:59.011199 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 474:605, ack 588, win 32038, options [nop,nop,TS val 13112292 ecr 2908216], length 131
23:44:59.047393 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 605, win 32044, options [nop,nop,TS val 2909752 ecr 13112292], length 0
23:45:02.263081 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [P.], seq 588:703, ack 605, win 32044, options [nop,nop,TS val 2910555 ecr 13112292], length 115
23:45:02.265653 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [.], ack 703, win 32038, options [nop,nop,TS val 13113106 ecr 2910555], length 0
23:45:04.015386 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 605:736, ack 703, win 32038, options [nop,nop,TS val 13113543 ecr 2910555], length 131
23:45:04.015469 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 736, win 32044, options [nop,nop,TS val 2910994 ecr 13113543], length 0
23:45:04.016358 IP 192.168.0.251.1194 > 192.168.2.13.60858: Flags [P.], seq 736:883, ack 703, win 32038, options [nop,nop,TS val 13113543 ecr 2910555], length 147
23:45:04.016385 IP 192.168.2.13.60858 > 192.168.0.251.1194: Flags [.], ack 883, win 32044, options [nop,nop,TS val 2910994 ecr 13113543], length 0
OpenVPN ipv4 connection, server, tcpdump -n -i tun0 | grep 1194
<silence>
OpenVPN ipv4 connection, client, tcpdump -n -i tun0 | grep 1194
<silence>
OpenVPN ipv6 connection, server, tcpdump -n -i wlan0_0 | grep 1194
<silence>
OpenVPN ipv6 connection, client, tcpdump -n -i wlan0 | grep 1194
<silence>
OpenVPN ipv6 connection, server, tcpdump -n -i tun1 | grep 1194
<silence>
OpenVPN ipv6 connection, client, tcpdump -n -i tun0 | grep 1194
00:02:44.231787 IP6 2001:xxxx:yyyy:606::8000.47390 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3496395985, win 14400, options [mss 1440,sackOK,TS val 3176048 ecr 0,nop,wscale 4], length 0
00:02:45.231409 IP6 2001:xxxx:yyyy:606::8000.47390 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3496395985, win 14400, options [mss 1440,sackOK,TS val 3176298 ecr 0,nop,wscale 4], length 0
00:02:47.235418 IP6 2001:xxxx:yyyy:606::8000.47390 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3496395985, win 14400, options [mss 1440,sackOK,TS val 3176799 ecr 0,nop,wscale 4], length 0
00:02:51.239423 IP6 2001:xxxx:yyyy:606::8000.47390 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3496395985, win 14400, options [mss 1440,sackOK,TS val 3177800 ecr 0,nop,wscale 4], length 0
00:02:59.234778 IP6 2001:xxxx:yyyy:606::8000.47391 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1195267018, win 14400, options [mss 1440,sackOK,TS val 3179798 ecr 0,nop,wscale 4], length 0
00:03:00.231415 IP6 2001:xxxx:yyyy:606::8000.47391 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1195267018, win 14400, options [mss 1440,sackOK,TS val 3180048 ecr 0,nop,wscale 4], length 0
00:03:02.235418 IP6 2001:xxxx:yyyy:606::8000.47391 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1195267018, win 14400, options [mss 1440,sackOK,TS val 3180549 ecr 0,nop,wscale 4], length 0
00:03:06.247409 IP6 2001:xxxx:yyyy:606::8000.47391 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1195267018, win 14400, options [mss 1440,sackOK,TS val 3181552 ecr 0,nop,wscale 4], length 0
00:03:14.237675 IP6 2001:xxxx:yyyy:606::8000.47392 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1616927214, win 14400, options [mss 1440,sackOK,TS val 3183549 ecr 0,nop,wscale 4], length 0
00:03:15.235417 IP6 2001:xxxx:yyyy:606::8000.47392 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1616927214, win 14400, options [mss 1440,sackOK,TS val 3183799 ecr 0,nop,wscale 4], length 0
00:03:17.239410 IP6 2001:xxxx:yyyy:606::8000.47392 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1616927214, win 14400, options [mss 1440,sackOK,TS val 3184300 ecr 0,nop,wscale 4], length 0
00:03:21.247411 IP6 2001:xxxx:yyyy:606::8000.47392 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1616927214, win 14400, options [mss 1440,sackOK,TS val 3185302 ecr 0,nop,wscale 4], length 0
00:03:29.240545 IP6 2001:xxxx:yyyy:606::8000.47393 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3319195732, win 14400, options [mss 1440,sackOK,TS val 3187300 ecr 0,nop,wscale 4], length 0
00:03:30.239423 IP6 2001:xxxx:yyyy:606::8000.47393 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3319195732, win 14400, options [mss 1440,sackOK,TS val 3187550 ecr 0,nop,wscale 4], length 0
00:03:32.243414 IP6 2001:xxxx:yyyy:606::8000.47393 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3319195732, win 14400, options [mss 1440,sackOK,TS val 3188051 ecr 0,nop,wscale 4], length 0
00:03:36.247408 IP6 2001:xxxx:yyyy:606::8000.47393 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3319195732, win 14400, options [mss 1440,sackOK,TS val 3189052 ecr 0,nop,wscale 4], length 0
00:03:44.243422 IP6 2001:xxxx:yyyy:606::8000.47395 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1162132979, win 14400, options [mss 1440,sackOK,TS val 3191051 ecr 0,nop,wscale 4], length 0
00:03:45.243430 IP6 2001:xxxx:yyyy:606::8000.47395 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1162132979, win 14400, options [mss 1440,sackOK,TS val 3191301 ecr 0,nop,wscale 4], length 0
00:03:47.247411 IP6 2001:xxxx:yyyy:606::8000.47395 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1162132979, win 14400, options [mss 1440,sackOK,TS val 3191802 ecr 0,nop,wscale 4], length 0
00:03:51.255407 IP6 2001:xxxx:yyyy:606::8000.47395 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1162132979, win 14400, options [mss 1440,sackOK,TS val 3192804 ecr 0,nop,wscale 4], length 0
00:03:59.246288 IP6 2001:xxxx:yyyy:606::8000.47396 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 351345591, win 14400, options [mss 1440,sackOK,TS val 3194801 ecr 0,nop,wscale 4], length 0
00:04:00.243418 IP6 2001:xxxx:yyyy:606::8000.47396 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 351345591, win 14400, options [mss 1440,sackOK,TS val 3195051 ecr 0,nop,wscale 4], length 0
00:04:02.247411 IP6 2001:xxxx:yyyy:606::8000.47396 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 351345591, win 14400, options [mss 1440,sackOK,TS val 3195552 ecr 0,nop,wscale 4], length 0
00:04:06.255416 IP6 2001:xxxx:yyyy:606::8000.47396 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 351345591, win 14400, options [mss 1440,sackOK,TS val 3196554 ecr 0,nop,wscale 4], length 0
00:04:14.249204 IP6 2001:xxxx:yyyy:606::8000.47397 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3346581964, win 14400, options [mss 1440,sackOK,TS val 3198552 ecr 0,nop,wscale 4], length 0
00:04:15.247407 IP6 2001:xxxx:yyyy:606::8000.47397 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3346581964, win 14400, options [mss 1440,sackOK,TS val 3198802 ecr 0,nop,wscale 4], length 0
00:04:17.251415 IP6 2001:xxxx:yyyy:606::8000.47397 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3346581964, win 14400, options [mss 1440,sackOK,TS val 3199303 ecr 0,nop,wscale 4], length 0
00:04:21.255417 IP6 2001:xxxx:yyyy:606::8000.47397 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3346581964, win 14400, options [mss 1440,sackOK,TS val 3200304 ecr 0,nop,wscale 4], length 0
00:04:29.252078 IP6 2001:xxxx:yyyy:606::8000.47398 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2357024051, win 14400, options [mss 1440,sackOK,TS val 3202303 ecr 0,nop,wscale 4], length 0
00:04:30.251414 IP6 2001:xxxx:yyyy:606::8000.47398 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2357024051, win 14400, options [mss 1440,sackOK,TS val 3202553 ecr 0,nop,wscale 4], length 0
00:04:32.255407 IP6 2001:xxxx:yyyy:606::8000.47398 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2357024051, win 14400, options [mss 1440,sackOK,TS val 3203054 ecr 0,nop,wscale 4], length 0
00:04:36.263406 IP6 2001:xxxx:yyyy:606::8000.47398 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2357024051, win 14400, options [mss 1440,sackOK,TS val 3204056 ecr 0,nop,wscale 4], length 0
00:04:44.254985 IP6 2001:xxxx:yyyy:606::8000.47399 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2906200856, win 14400, options [mss 1440,sackOK,TS val 3206053 ecr 0,nop,wscale 4], length 0
00:04:45.251405 IP6 2001:xxxx:yyyy:606::8000.47399 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2906200856, win 14400, options [mss 1440,sackOK,TS val 3206303 ecr 0,nop,wscale 4], length 0
00:04:47.255395 IP6 2001:xxxx:yyyy:606::8000.47399 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2906200856, win 14400, options [mss 1440,sackOK,TS val 3206804 ecr 0,nop,wscale 4], length 0
00:04:51.263413 IP6 2001:xxxx:yyyy:606::8000.47399 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2906200856, win 14400, options [mss 1440,sackOK,TS val 3207806 ecr 0,nop,wscale 4], length 0
00:04:59.257891 IP6 2001:xxxx:yyyy:606::8000.47401 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1776794800, win 14400, options [mss 1440,sackOK,TS val 3209804 ecr 0,nop,wscale 4], length 0
00:05:00.255416 IP6 2001:xxxx:yyyy:606::8000.47401 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1776794800, win 14400, options [mss 1440,sackOK,TS val 3210054 ecr 0,nop,wscale 4], length 0
00:05:02.259415 IP6 2001:xxxx:yyyy:606::8000.47401 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1776794800, win 14400, options [mss 1440,sackOK,TS val 3210555 ecr 0,nop,wscale 4], length 0
00:05:06.263416 IP6 2001:xxxx:yyyy:606::8000.47401 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1776794800, win 14400, options [mss 1440,sackOK,TS val 3211556 ecr 0,nop,wscale 4], length 0
00:05:14.260854 IP6 2001:xxxx:yyyy:606::8000.47402 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 75453508, win 14400, options [mss 1440,sackOK,TS val 3213555 ecr 0,nop,wscale 4], length 0
00:05:15.259397 IP6 2001:xxxx:yyyy:606::8000.47402 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 75453508, win 14400, options [mss 1440,sackOK,TS val 3213805 ecr 0,nop,wscale 4], length 0
00:05:17.263394 IP6 2001:xxxx:yyyy:606::8000.47402 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 75453508, win 14400, options [mss 1440,sackOK,TS val 3214306 ecr 0,nop,wscale 4], length 0
00:05:21.271408 IP6 2001:xxxx:yyyy:606::8000.47402 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 75453508, win 14400, options [mss 1440,sackOK,TS val 3215308 ecr 0,nop,wscale 4], length 0
00:05:29.263746 IP6 2001:xxxx:yyyy:606::8000.47403 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 4204410216, win 14400, options [mss 1440,sackOK,TS val 3217306 ecr 0,nop,wscale 4], length 0
00:05:30.263404 IP6 2001:xxxx:yyyy:606::8000.47403 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 4204410216, win 14400, options [mss 1440,sackOK,TS val 3217556 ecr 0,nop,wscale 4], length 0
00:05:32.267411 IP6 2001:xxxx:yyyy:606::8000.47403 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 4204410216, win 14400, options [mss 1440,sackOK,TS val 3218057 ecr 0,nop,wscale 4], length 0
00:05:36.279412 IP6 2001:xxxx:yyyy:606::8000.47403 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 4204410216, win 14400, options [mss 1440,sackOK,TS val 3219060 ecr 0,nop,wscale 4], length 0
00:05:44.266678 IP6 2001:xxxx:yyyy:606::8000.47404 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 380128810, win 14400, options [mss 1440,sackOK,TS val 3221056 ecr 0,nop,wscale 4], length 0
00:05:45.263319 IP6 2001:xxxx:yyyy:606::8000.47404 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 380128810, win 14400, options [mss 1440,sackOK,TS val 3221306 ecr 0,nop,wscale 4], length 0
00:05:47.267384 IP6 2001:xxxx:yyyy:606::8000.47404 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 380128810, win 14400, options [mss 1440,sackOK,TS val 3221807 ecr 0,nop,wscale 4], length 0
00:05:51.271421 IP6 2001:xxxx:yyyy:606::8000.47404 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 380128810, win 14400, options [mss 1440,sackOK,TS val 3222808 ecr 0,nop,wscale 4], length 0
00:05:59.269641 IP6 2001:xxxx:yyyy:606::8000.47405 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2366923786, win 14400, options [mss 1440,sackOK,TS val 3224807 ecr 0,nop,wscale 4], length 0
00:06:00.267414 IP6 2001:xxxx:yyyy:606::8000.47405 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2366923786, win 14400, options [mss 1440,sackOK,TS val 3225057 ecr 0,nop,wscale 4], length 0
00:06:02.271418 IP6 2001:xxxx:yyyy:606::8000.47405 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2366923786, win 14400, options [mss 1440,sackOK,TS val 3225558 ecr 0,nop,wscale 4], length 0
00:06:06.279419 IP6 2001:xxxx:yyyy:606::8000.47405 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2366923786, win 14400, options [mss 1440,sackOK,TS val 3226560 ecr 0,nop,wscale 4], length 0
00:06:14.272536 IP6 2001:xxxx:yyyy:606::8000.47406 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1834626202, win 14400, options [mss 1440,sackOK,TS val 3228558 ecr 0,nop,wscale 4], length 0
00:06:15.271401 IP6 2001:xxxx:yyyy:606::8000.47406 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1834626202, win 14400, options [mss 1440,sackOK,TS val 3228808 ecr 0,nop,wscale 4], length 0
00:06:17.275406 IP6 2001:xxxx:yyyy:606::8000.47406 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1834626202, win 14400, options [mss 1440,sackOK,TS val 3229309 ecr 0,nop,wscale 4], length 0
00:06:21.287417 IP6 2001:xxxx:yyyy:606::8000.47406 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 1834626202, win 14400, options [mss 1440,sackOK,TS val 3230312 ecr 0,nop,wscale 4], length 0
00:06:29.275393 IP6 2001:xxxx:yyyy:606::8000.47408 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2024496180, win 14400, options [mss 1440,sackOK,TS val 3232309 ecr 0,nop,wscale 4], length 0
00:06:30.275417 IP6 2001:xxxx:yyyy:606::8000.47408 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2024496180, win 14400, options [mss 1440,sackOK,TS val 3232559 ecr 0,nop,wscale 4], length 0
00:06:32.279423 IP6 2001:xxxx:yyyy:606::8000.47408 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2024496180, win 14400, options [mss 1440,sackOK,TS val 3233060 ecr 0,nop,wscale 4], length 0
00:06:36.287415 IP6 2001:xxxx:yyyy:606::8000.47408 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2024496180, win 14400, options [mss 1440,sackOK,TS val 3234062 ecr 0,nop,wscale 4], length 0
00:06:44.278220 IP6 2001:xxxx:yyyy:606::8000.47409 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3289771924, win 14400, options [mss 1440,sackOK,TS val 3236059 ecr 0,nop,wscale 4], length 0
00:06:45.275408 IP6 2001:xxxx:yyyy:606::8000.47409 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3289771924, win 14400, options [mss 1440,sackOK,TS val 3236309 ecr 0,nop,wscale 4], length 0
00:06:47.279404 IP6 2001:xxxx:yyyy:606::8000.47409 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3289771924, win 14400, options [mss 1440,sackOK,TS val 3236810 ecr 0,nop,wscale 4], length 0
00:06:51.287415 IP6 2001:xxxx:yyyy:606::8000.47409 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 3289771924, win 14400, options [mss 1440,sackOK,TS val 3237812 ecr 0,nop,wscale 4], length 0
00:06:59.281095 IP6 2001:xxxx:yyyy:606::8000.47410 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2749165943, win 14400, options [mss 1440,sackOK,TS val 3239810 ecr 0,nop,wscale 4], length 0
00:07:00.279409 IP6 2001:xxxx:yyyy:606::8000.47410 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2749165943, win 14400, options [mss 1440,sackOK,TS val 3240060 ecr 0,nop,wscale 4], length 0
00:07:02.283412 IP6 2001:xxxx:yyyy:606::8000.47410 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2749165943, win 14400, options [mss 1440,sackOK,TS val 3240561 ecr 0,nop,wscale 4], length 0
00:07:06.295415 IP6 2001:xxxx:yyyy:606::8000.47410 > 2001:xxxx:yyyy:606::1.1194: Flags [S], seq 2749165943, win 14400, options [mss 1440,sackOK,TS val 3241564 ecr 0,nop,wscale 4], length 0
For ipv4, I see client and server sending control messages to each other via wifi, wlan0_0 and wlan0, respectively.
For ipv6, I see the client trying to send control messages to the server via its tun0 interface, that never reach the server. There's total silence on the server side.
So, ipv6 behaviour is different, and strange. I am not an expert, and I do not understand how this happens and what I can do now. I tried to set routes client side to force packets sent to the server ip to go through wlan0 rather than tun0, no success.
Any ideas?
Cheers,
Robert
