When trying to establish a connection by connecting to the IPv6 address of server and without mentioning the local-host option, then the connection is not establishing
Server configuration:
set interfaces openvpn vtun20 encryption cipher 'aes256' set interfaces openvpn vtun20 hash 'sha512' set interfaces openvpn vtun20 mode 'server' set interfaces openvpn vtun20 persistent-tunnel set interfaces openvpn vtun20 server subnet '2001:db8:abcd:10::/64' set interfaces openvpn vtun20 server subnet '10.10.2.0/24' set interfaces openvpn vtun20 server topology 'subnet' set interfaces openvpn vtun20 tls ca-certificate 'root-ca' set interfaces openvpn vtun20 tls certificate 'server1' set interfaces openvpn vtun20 tls dh-params 'dh-1
Client Configuration:
set interfaces openvpn vtun10 encryption cipher 'aes256' set interfaces openvpn vtun10 hash 'sha512' set interfaces openvpn vtun10 mode 'client' set interfaces openvpn vtun10 remote-host '2001:db8::1' set interfaces openvpn vtun10 remote-port '1194' set interfaces openvpn vtun10 tls ca-certificate 'root-ca' set interfaces openvpn vtun10 tls certificate 'cbranch1'
After adding option "proto udp6" , connection establishes:
set interfaces openvpn vtun20 openvpn-option 'proto udp6'
Listening port with 'proto udp6'
udp UNCONN 0 0 *:1194 *:*
and without the 'proto udp6' option:
udp UNCONN 0 0 0.0.0.0:1194 0.0.0.0:*
When mentioned the local-host with ipv6 address
udp UNCONN 0 0 [2001:db8::1]:1194 [::]:*
In the OpenVPN server logs, it shows unable to determine the protocol:
Mar 21 09:17:20 openvpn-vtun20[97459]: net_addr_v6_add: 2001:db8:abcd:10::1/64 dev vtun20 Mar 21 09:17:20 openvpn-vtun20[97459]: Could not determine IPv4/IPv6 protocol. Using AF_INET Mar 21 09:17:20 openvpn-vtun20[97459]: Socket Buffers: R=[212992->212992] S=[212992->212992] Mar 21 09:17:20 openvpn-vtun20[97459]: UDPv4 link local (bound): [AF_INET][undef]:1194 Mar 21 09:17:20 openvpn-vtun20[97459]: UDPv4 link remote: [AF_UNSPEC] Mar 21 09:17:20 openvpn-vtun20[97459]: MULTI: multi_init called, r=256 v=256 Mar 21 09:17:20 openvpn-vtun20[97459]: IFCONFIG POOL IPv6: base=2001:db8:abcd:10::1000 size=65536 netbits=64 Mar 21 09:17:20 openvpn-vtun20[97459]: Initialization Sequence Completed Mar 21 09:21:02 openvpn-vtun20[97459]: read UDPv4 [CMSG=8|ECONNREFUSED|CMSG=8|ECONNREFUSED]: Connection refused (fd=7,code=111) Mar 21 09:21:06 openvpn-vtun20[97459]: read UDPv4 [CMSG=8|ECONNREFUSED|CMSG=8|ECONNREFUSED]: Connection refused (fd=7,code=111) Mar 21 09:21:14 openvpn-vtun20[97459]: read UDPv4 [CMSG=8|ECONNREFUSED|CMSG=8|ECONNREFUSED]: Connection refused (fd=7,code=111) Mar 21 09:21:30 openvpn-vtun20[97459]: read UDPv4 [CMSG=8|ECONNREFUSED|CMSG=8|ECONNREFUSED]: Connection refused (fd=7,code=111)
On client side:
Mar 21 09:17:20 openvpn-vtun20[97459]: net_addr_v6_add: 2001:db8:abcd:10::1/64 dev vtun20 Mar 21 09:17:20 openvpn-vtun20[97459]: Could not determine IPv4/IPv6 protocol. Using AF_INET Mar 21 09:17:20 openvpn-vtun20[97459]: Socket Buffers: R=[212992->212992] S=[212992->212992] Mar 21 09:17:20 openvpn-vtun20[97459]: UDPv4 link local (bound): [AF_INET][undef]:1194 Mar 21 09:17:20 openvpn-vtun20[97459]: UDPv4 link remote: [AF_UNSPEC] Mar 21 09:17:20 openvpn-vtun20[97459]: MULTI: multi_init called, r=256 v=256 Mar 21 09:17:20 openvpn-vtun20[97459]: IFCONFIG POOL IPv6: base=2001:db8:abcd:10::1000 size=65536 netbits=64 Mar 21 09:17:20 openvpn-vtun20[97459]: Initialization Sequence Completed Mar 21 09:21:02 openvpn-vtun20[97459]: read UDPv4 [CMSG=8|ECONNREFUSED|CMSG=8|ECONNREFUSED]: Connection refused (fd=7,code=111) Mar 21 09:21:06 openvpn-vtun20[97459]: read UDPv4 [CMSG=8|ECONNREFUSED|CMSG=8|ECONNREFUSED]: Connection refused (fd=7,code=111)
Working logs from the server side:
Mar 21 10:23:38 openvpn-vtun20[99360]: TUN/TAP device vtun20 opened Mar 21 10:23:38 openvpn-vtun20[99360]: net_iface_mtu_set: mtu 1500 for vtun20 Mar 21 10:23:38 openvpn-vtun20[99360]: net_iface_up: set vtun20 up Mar 21 10:23:38 openvpn-vtun20[99360]: net_addr_v6_add: 2001:db8:abcd:10::1/64 dev vtun20 Mar 21 10:23:38 openvpn-vtun20[99360]: Socket Buffers: R=[212992->212992] S=[212992->212992] Mar 21 10:23:38 openvpn-vtun20[99360]: setsockopt(IPV6_V6ONLY=0) Mar 21 10:23:38 openvpn-vtun20[99360]: UDPv6 link local (bound): [AF_INET6][undef]:1194 Mar 21 10:23:38 openvpn-vtun20[99360]: UDPv6 link remote: [AF_UNSPEC] Mar 21 10:23:38 openvpn-vtun20[99360]: MULTI: multi_init called, r=256 v=256 Mar 21 10:23:38 openvpn-vtun20[99360]: IFCONFIG POOL IPv6: base=2001:db8:abcd:10::1000 size=65536 netbits=64 Mar 21 10:23:38 openvpn-vtun20[99360]: Initialization Sequence Completed