I have reinstalled OpenWrt on my Raspi to be sure, that my weird problem is not connected with some mistake in configuration.
Now I have following network configuration:
-
Raspi OpenWrt:
WAN - Huawei 3327h dongle - NCM - IPv6 + 464xlat tunneling
LAN - static ip 192.168.0.1 with DHCP for 1 user limit
-
Asus RT-AC68U with newest AsusWRT:
WAN - ethernet with Raspi (NAT)
LAN & WiFi - all connected devices in home - DHCP in subnet 192.168.1.0
For connection and pinging i'm using IPv6 and More App for Android
I have installed tcpdump and run your proposed command with following result:
Trying to connect with tcp 5001 port from 'mobile:phone:ipv6' to 'synology:ipv6'
12:37:09.078141 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703869156 ecr 0,nop,wscale 8], length 0
12:37:09.078320 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703869156 ecr 0,nop,wscale 8], length 0
12:37:09.078337 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703869156 ecr 0,nop,wscale 8], length 0
12:37:09.079231 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4326038 ecr 703869156,nop,wscale 7], length 0
12:37:09.079231 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4326038 ecr 703869156,nop,wscale 7], length 0
12:37:09.079334 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4326038 ecr 703869156,nop,wscale 7], length 0
12:37:10.078396 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4327038 ecr 703869156,nop,wscale 7], length 0
12:37:10.078396 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4327038 ecr 703869156,nop,wscale 7], length 0
12:37:10.078467 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4327038 ecr 703869156,nop,wscale 7], length 0
12:37:10.308369 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703870183 ecr 0,nop,wscale 8], length 0
12:37:10.308425 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703870183 ecr 0,nop,wscale 8], length 0
12:37:10.308434 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703870183 ecr 0,nop,wscale 8], length 0
12:37:10.309282 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4327268 ecr 703869156,nop,wscale 7], length 0
12:37:10.309282 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4327268 ecr 703869156,nop,wscale 7], length 0
12:37:10.309351 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4327268 ecr 703869156,nop,wscale 7], length 0
12:37:11.748430 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40602: Flags [S.], seq 2271310086, ack 1846436215, win 28560, options [mss 1440,sackOK,TS val 4328708 ecr 703856748,nop,wscale 7], length 0
12:37:11.748430 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40602: Flags [S.], seq 2271310086, ack 1846436215, win 28560, options [mss 1440,sackOK,TS val 4328708 ecr 703856748,nop,wscale 7], length 0
12:37:11.748506 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40602: Flags [S.], seq 2271310086, ack 1846436215, win 28560, options [mss 1440,sackOK,TS val 4328708 ecr 703856748,nop,wscale 7], length 0
12:37:12.140111 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703872199 ecr 0,nop,wscale 8], length 0
12:37:12.140189 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703872199 ecr 0,nop,wscale 8], length 0
12:37:12.140198 IP6 'mobile:phone:ipv6'.40604 > 'synology:ipv6'.5001: Flags [S], seq 6498874, win 65535, options [mss 1220,sackOK,TS val 703872199 ecr 0,nop,wscale 8], length 0
12:37:12.140913 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4329100 ecr 703869156,nop,wscale 7], length 0
12:37:12.140913 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4329100 ecr 703869156,nop,wscale 7], length 0
12:37:12.140987 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4329100 ecr 703869156,nop,wscale 7], length 0
12:37:14.140519 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4331100 ecr 703869156,nop,wscale 7], length 0
12:37:14.140519 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4331100 ecr 703869156,nop,wscale 7], length 0
12:37:14.140704 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40604: Flags [S.], seq 26227674, ack 6498875, win 28560, options [mss 1440,sackOK,TS val 4331100 ecr 703869156,nop,wscale 7], length 0
^C
27 packets captured
40 packets received by filter
5 packets dropped by kernel
Result: Port unreachable
Pinging 'synology:ipv6' from 'mobile:phone:ipv6'
12:39:32.038546 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 0, length 8
12:39:32.038659 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 0, length 8
12:39:32.038677 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 0, length 8
12:39:33.048546 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 8
12:39:33.048615 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 8
12:39:33.048625 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 8
12:39:34.173649 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 8
12:39:34.173781 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 8
12:39:34.173794 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 8
12:39:35.089596 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 8
12:39:35.089754 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 8
12:39:35.089773 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 8
12:39:36.118584 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 8
12:39:36.118658 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 8
12:39:36.118668 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 8
12:39:37.125812 IP6 'openwrt:ipv6:gateway' > 'synology:ipv6': ICMP6, neighbor solicitation, who has 'synology:ipv6', length 32
12:39:37.125835 IP6 'openwrt:ipv6:gateway' > 'synology:ipv6': ICMP6, neighbor solicitation, who has 'synology:ipv6', length 32
12:39:37.142573 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 8
12:39:37.142652 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 8
12:39:37.142662 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 8
12:39:37.143344 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 8
12:39:37.143344 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 8
12:39:37.143402 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 8
12:39:37.249571 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 64
12:39:37.249658 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 64
12:39:37.249668 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 64
12:39:37.250325 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 1, length 64
12:39:37.250325 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 1, length 64
12:39:37.250384 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 1, length 64
12:39:38.155832 IP6 'openwrt:ipv6:gateway' > 'synology:ipv6': ICMP6, neighbor solicitation, who has 'synology:ipv6', length 32
12:39:38.155860 IP6 'openwrt:ipv6:gateway' > 'synology:ipv6': ICMP6, neighbor solicitation, who has 'synology:ipv6', length 32
12:39:38.242556 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 64
12:39:38.242609 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 64
12:39:38.242616 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 64
12:39:38.243297 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 2, length 64
12:39:38.243297 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 2, length 64
12:39:38.243355 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 2, length 64
12:39:39.248579 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 64
12:39:39.248638 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 64
12:39:39.248647 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 64
12:39:39.249278 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 3, length 64
12:39:39.249278 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 3, length 64
12:39:39.249336 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 3, length 64
12:39:40.258614 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 64
12:39:40.258673 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 64
12:39:40.258681 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 64
12:39:40.260059 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 4, length 64
12:39:40.260059 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 4, length 64
12:39:40.260119 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 4, length 64
12:39:41.268566 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 64
12:39:41.268628 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 64
12:39:41.268637 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 64
12:39:41.269270 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 64
12:39:41.269270 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 64
12:39:41.269330 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 64
^C
55 packets captured
67 packets received by filter
4 packets dropped by kernel
Result: Ping works good
Trying to connect while Pinging
12:40:55.180016 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 0, length 8
12:40:55.180112 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 0, length 8
12:40:55.180122 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 0, length 8
12:40:55.180831 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 0, length 8
12:40:55.180831 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 0, length 8
12:40:55.180896 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 0, length 8
12:40:55.268934 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 64
12:40:55.269003 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 64
12:40:55.269012 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 1, length 64
12:40:55.269690 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 1, length 64
12:40:55.269690 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 1, length 64
12:40:55.269741 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 1, length 64
12:40:56.283962 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 64
12:40:56.284014 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 64
12:40:56.284024 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 2, length 64
12:40:56.284728 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 2, length 64
12:40:56.284728 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 2, length 64
12:40:56.284786 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 2, length 64
12:40:57.281920 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 64
12:40:57.281984 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 64
12:40:57.281993 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 3, length 64
12:40:57.282617 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 3, length 64
12:40:57.282617 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 3, length 64
12:40:57.282678 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 3, length 64
12:40:58.296965 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 64
12:40:58.297034 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 64
12:40:58.297043 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 4, length 64
12:40:58.297723 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 4, length 64
12:40:58.297723 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 4, length 64
12:40:58.297777 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 4, length 64
12:40:59.290935 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 64
12:40:59.291003 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 64
12:40:59.291012 IP6 'mobile:phone:ipv6' > 'synology:ipv6': ICMP6, echo request, seq 5, length 64
12:40:59.291709 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 64
12:40:59.291709 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 64
12:40:59.291771 IP6 'synology:ipv6' > 'mobile:phone:ipv6': ICMP6, echo reply, seq 5, length 64
12:40:59.343940 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [S], seq 3586667046, win 65535, options [mss 1220,sackOK,TS val 704099431 ecr 0,nop,wscale 8], length 0
12:40:59.344026 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [S], seq 3586667046, win 65535, options [mss 1220,sackOK,TS val 704099431 ecr 0,nop,wscale 8], length 0
12:40:59.344035 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [S], seq 3586667046, win 65535, options [mss 1220,sackOK,TS val 704099431 ecr 0,nop,wscale 8], length 0
12:40:59.344719 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40628: Flags [S.], seq 3738545072, ack 3586667047, win 28560, options [mss 1440,sackOK,TS val 4556307 ecr 704099431,nop,wscale 7], length 0
12:40:59.344719 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40628: Flags [S.], seq 3738545072, ack 3586667047, win 28560, options [mss 1440,sackOK,TS val 4556307 ecr 704099431,nop,wscale 7], length 0
12:40:59.344812 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40628: Flags [S.], seq 3738545072, ack 3586667047, win 28560, options [mss 1440,sackOK,TS val 4556307 ecr 704099431,nop,wscale 7], length 0
12:40:59.384929 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [.], ack 1, win 338, options [nop,nop,TS val 704099470 ecr 4556307], length 0
12:40:59.384977 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [.], ack 1, win 338, options [nop,nop,TS val 704099470 ecr 4556307], length 0
12:40:59.384985 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [.], ack 1, win 338, options [nop,nop,TS val 704099470 ecr 4556307], length 0
12:40:59.389923 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [F.], seq 1, ack 1, win 338, options [nop,nop,TS val 704099471 ecr 4556307], length 0
12:40:59.389972 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [F.], seq 1, ack 1, win 338, options [nop,nop,TS val 704099471 ecr 4556307], length 0
12:40:59.389981 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [F.], seq 1, ack 1, win 338, options [nop,nop,TS val 704099471 ecr 4556307], length 0
12:40:59.390579 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40628: Flags [F.], seq 1, ack 2, win 224, options [nop,nop,TS val 4556353 ecr 704099471], length 0
12:40:59.390579 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40628: Flags [F.], seq 1, ack 2, win 224, options [nop,nop,TS val 4556353 ecr 704099471], length 0
12:40:59.390631 IP6 'synology:ipv6'.5001 > 'mobile:phone:ipv6'.40628: Flags [F.], seq 1, ack 2, win 224, options [nop,nop,TS val 4556353 ecr 704099471], length 0
12:40:59.429961 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [.], ack 2, win 338, options [nop,nop,TS val 704099517 ecr 4556353], length 0
12:40:59.430010 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [.], ack 2, win 338, options [nop,nop,TS val 704099517 ecr 4556353], length 0
12:40:59.430019 IP6 'mobile:phone:ipv6'.40628 > 'synology:ipv6'.5001: Flags [.], ack 2, win 338, options [nop,nop,TS val 704099517 ecr 4556353], length 0
^C
54 packets captured
66 packets received by filter
4 packets dropped by kernel
Result: Port is open